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Discussion Starter #1
Iv'e been eyeing doing this swap for my 08 TBSS for a long time. I purchased Jesse's (TBMSport) conversion module and harness quite a while ago and planned to do all the rest of the work myself.

I recently purchased a used RWD 6L90 from a 07 6.0L Silverado 2500, with 134,000 miles on it. I plan to rebuild it, and do what's necessary to make it work on my RWD 08 TBSS.

I will try to chronicle this build as I go. It's going to be a bit of a longer term build as I have very limited time.
 

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Discussion Starter #3
Lots of reasons really. First priority, better performance. I want this truck to rip off astounding 60 foot times and trim down the 1/4 a bunch. So, its not only getting the 6 speed, but a stall converter, and definitely a good set of stickies.

Thing is, my TBSS is completely stock. It's on its original 4L70 and I am at 153k miles on it, and I am not by any means easy on it. Everyday has many WOT moments, and tons of 3-1/2-1 downshifts. It's going to bite me eventually. Am I happy with the 4L70? Not particularly. It's been a solid trooper though for me.

If I were to sum up this trucks straight line performance, I'd say the transmission is the worst thing about it. Its not particularly quick off the line. 2.226 was my best 60' No tire spin at all. It has a good bite on the initial take off, but falls flat immediately between ~10-20 MPH. After that, the engine gets into the power band and feels great till it shifts into 2nd at about 43. Dead spot between there and 55, but feels great up to about 75 where the engine is running out of breath. Shifts into 3rd at about 82. Finishes the quarter 14.511 @ 96.21 MPH. I did burn up 3rd gear once, but a little line pressure increase going into 3rd made that so it never happened again.

The 6L80-90's have a real stump puller of a first gear, and less of a step into second gear. Third gear is actually really close to the 4L70's second gear. So it should do a ton better nailing down a really hard launch and stay solidly in the power band through those critical shifts. I really look forward the possibilities with it.

Reliability is also an important factor to me. I am doing a rebuild with most of the little fixes, updates and improvements available for the 6L90 that I reasonably want. This transmission is incredibly way overbuilt compared to the 4L70, and I bet its easily comparable to a 4L80 for brute strength, but it actually has good ratios.

I also plan on fine tuning the lockup converter to make a proper 3200-3600 torque converter almost seem like it doesn't have a stall at all. The 6L80-90's software has flexibility that is far beyond what the 4L70 was given. It even allows you to lock the converter in 1st gear if you want. Plus tap shift, gear holding, and hill braking.

Really its not such a hard choice for me.
 

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You will probably want to look into a new gear ratio. With the 4.10 in the TBSS, first gear will be completely useless on a 6l. A set of 3.73's would be perfect and you'll get a lot better fuel mileage cruising and your launches will be better. I personally would never do a 6l swap on these trucks because I basically hate them, lol. My choice would be a built 4l80 but that's just my opinion and I understand why you would want to do the swap and I'm excited to see the build. The 6l90 is a beast in stock form and will easily hold 650-700whp if not higher for a long time. There's guys pushing stock 6l80's to 800whp albeit in a lot lighter cars but they are taking some serious abuse. My car is putting down 640whp on a stock 6l80 with stock stall and it doesn't seem to skip a beat. Good luck with the build and keep us posted on the progress!
 
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I would have liked to do a 6L, but it seems its still fairly expensive, not a ton of people have put them in trailblazers, and supposedly a 4l80 will hold more power longer.
I sure would love the shorter gearing though....One day...
 

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Discussion Starter #6
I agree that the best combo would be to put taller gearing with the 6L. Perhaps 3.23 or so, just somewhere in the 3's. That makes all kinds of sense. It's just better all around. I don't know if first gear is useless or not yet. It really depends on the torque converter and if the tires can plant themselves with that much torque being applied. The engine also needs to be a snappy rever compared to the expected duration of first gear. I'll see how it all turns out. Might be a gear swap in the future for me if I hate it as is.

That being said, I like that the 6L shifts 1-2 by applying an additional clutch to first gear. This causes the sprag to overrun and that's the shift. This means you can have little (or no?) torque management employed for 1-2 and have it be a short and aggressive shift. All other upshifts are phasing a clutch out while engaging another. Too much overlap binds the transmission and wears the clutches out. Too little causes shift flare which also wears clutches. It's not as simple as the old 4 speeds were. Other than the fact that it's very sensitive to tuning and mechanical changes, I don't get why people aren't particularly fond of the 6L transmissions. But I admittedly haven't driven with one yet.

My goal is to have the engine stay perfectly stock, but knock over a second off the quarter. I feel like I can make the greatest improvements in the launch and the time spent at better gearing at peak power will net some pretty impressive results. And I can relax knowing it's not going to 4L70 on me.
 

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I did 3.43's with my 6L80E. It's still a steeper first gear than the factory TBSS and is the lowest (numerical) ratio you can do with an AWD. They feel great and are still capable of burnouts.

Two quick things-
The CTS-V torque converter drives very nicely. If you want a relatively mild, but performance oriented converter, these are cheap and reliable.
The CTS-V transmission cooler lines are an almost perfect fit. I tried these and some Camaro lines and the CTS-V lines were much better. If you have a fenderwell cooler, you can run the lines straight into it.

Good luck with your swap. If you have any questions, you're more than welcome to send me a PM.

Tim
 

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secret squirrel
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sounds interesting..
 

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Discussion Starter #9
I've been thinking of using one of these cooler line manifolds to do the lines. Seems easy. But I do want to add a trans cooler inline.


I've been looking at the CTS-V converters too. Also, been looking at FTI, Circle D, and a few others. It seems like there isn't a whole lot of choice out there. and prices are generally around $800-1200 for a really good converter. I want something around a 3200 RPM stall. This is the best thing I've found so far for what I want. Its only $550 too!
Circle D's 278mm 6L80 LS torque converter. 2800-3200 RPM stall.
Circle D Specialties High Performance 278mm Torque Converter for GM 6L80 LS

I've been spending a lot of time pouring over the ATSG manual, and studying tunes on HP tuners for various stock applications for the 6L80's and 90's. Trying to prepare to tweak the TCM settings to make a 3200 RPM stall work better with a daily driver. The lock up is very flexible in how it allows it to be used fortunately. Heck, you can have it lock up in first gear if you want.

So far, I've opened the transmission up and popped the the snap rings off the clutches and had a peak at the clutch packs. They were all in perfect shape. I threw them back together while I wait for some transmission parts to show up. This seems to be a fairly simple transmission to rebuild. A bit easier than the 4L60's in my opinion.
 

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Nice to see someone trying something different. From Vegas huh?
 

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I've been thinking of using one of these cooler line manifolds to do the lines. Seems easy. But I do want to add a trans cooler inline.

/url]
I bought one of those and had thought about using it. I didn't because I wasn't sure that it would clear the headers and didn't want to risk a leak. I've melted teflon lined SS braided hose that was too close to an exhaust system before and blew an engine because of it...

The link below has pictures of the headers vs. the transmission cooler lines.

https://www.icloud.com/sharedalbum/#B0s5oqs3qlcyRU

Tim
 

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Discussion Starter #12
That's good advice... Hadn't considered the relation of the exhaust VS the trans cooler lines. Maybe I'll just do the CTS-V lines. Splicing tubing doesn't bother me at all.

As I said before, I have already torn down the transmission, and am waiting for enough funds to buy everything I need to get the transmission up to date. The 6L80/90 isn't a cheap transmission to rebuild compared to the 4Lx0. I had a few moments today to do a quick task to get me started on wrapping my head around what the engine/transmission programming will look like.

So, I decided to get out my HP tuner, plug it in and did a Read Vehicle to pull my current program from my truck.

I put the TEHCM on my truck, plugged in the harness from TBMSports T42-T43 adaptor. Then moved the connector from the 4L70's TCM to T42-T43 adaptor. For a little bit of added comfort I also grounded the TEHCM to the engine just in case it relies on case grounding for operation. Then I did another Read Vehicle.



It immediately picked up on the fact that the truck has a T43 TCM, and it read it just fine.


And sure enough, when I went to trans parameters on the VCM editor, it had all 6L80-90 tuning parameters. It also didn't care about the TCM change as far as licensing credits is concerned. So tuning won't be a problem.

I also popped into the VCM Scanner software to see if that also had 6L80/90 properties. Sure enough, manual control offered gear control 1 - 6. So the module is pretty much plug and play.
 

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I did 3.43's with my 6L80E. It's still a steeper first gear than the factory TBSS and is the lowest (numerical) ratio you can do with an AWD.
I have to second this. My V is an automatic so it has a 3.23 rear end. First is mostly useless with high performance summer tires as it just spins unless you really feather the gas pedal. It does much better with drag radials, but my TBSS has a slightly faster 60' due to better traction.
 

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Discussion Starter #14 (Edited)
Ok, this is where the fun begins. Big posts ahead. I'm not going to bore you with all the details about disassembly. There is a really useful video on youtube that covers disassembly really well. Search for "6L80-E Transmission"

I purchased a ATSG 6L80 manual, this has a lot of good info in it to familiarize the rebuilder with the intricacies of a particular transmission.

I decided early on that I was going to go through this transmission and fix all the known trouble areas, and replace all seals and clutch frictions. I didn't realize before I took it apart, that this transmission was actually in absolutely perfect condition. I could have just shoved the transmission in, turned the key and enjoyed. But, I'm still going to go through and get this transmission up to better than new condition, even do a few preparations that should support a bunch more power if I decide to upgrade the engine.

This transmission seems to be the easiest unit to disassemble that I have ever come across. I gutted it in 20 minutes. The only thing that tripped me up was the gigantic snap ring that holds the 2-6/Low Reverse center housing in place. That thing is no Joke. I'm going to have to make a tool to reinstall it.
Here's the transmission all gutted out. I put some of the sub assemblies together to save space on my small work bench. I put the case back together empty to easily take measurements and move the case around.





This is the basic rebuild kit I am using. It is a banner kit, with frictions. It includes every soft part for every version of this transmission. There isn't much different amongst all models of the 6L80/90. Any 6L90 rebuild kit will work on any 6L80, minus the pan gasket. You'll just have some extra clutch plates, one per clutch.


Some more stuff. The other thing I am replacing is all the pistons. Shown here on the cardboard. The rest of the stuff is supplied by Sonnax, and its all for fixes and improvements to the transmission. The improvements from Sonnax include:
104984-01. 1234 Billet Piston, Replaces the factory piston which was way under built and tends to crack and leak.
10496001K. 456 Piston kit, Includes all kinds of stuff to keep the frictions from deflecting, and coning. 456 is notorious for burning up.
6l456l90ZIP. ZIP kit, Includes A LOT of valve body improvements.
6L80LB1. Line Booster kit, Improves line pressure response.
104534-HD. HD Pump slide spring, Keeps the pump from unintentionally decreasing displacement when the engine RPMs are high.
124740TL30. Pressure switch rebuild kit, with tools. They tend to malfunction, causing codes.
GM 24258550. IMS range (PRNDL) switch. Early 6L's had issues with the contacts oxidizing. A later part number corrected this issue.


First thing I am going through is the front case and pump assembly.
Why not start with the front seal?
Pop the snap ring


I used a slide hammer to pop the front seal out. It was a little overkill, the seal isn't in very tight. The new seal seemed to go in a little easy too. I hope it doesn't leak!


I didn't NEED to change the line dust seals but I did because, why not.


New ones in, I used a socket and hammer to set them in straight.


Next up, I wiped clean the pump parts.


Sat the pump rotor in, with the plastic side down, one pump ring in place on the bottom, one on top.


I have to replace the rubber O-ring, and the slide face seal, and the slide actuator seal. I put the seals in place then pushed the tapered slide pivot pin to compress the actuator seal. Easy stuff.


The new HD pump slide spring vs the original.


It was a bit hard to compress, but I did it with this, then pushed it into place.


I personally like to put the pump vanes in with the same contact surfaces. It was pretty obvious which way they go. Two shiny spots to the inside.


Pump assembly complete.


Good time to bury the pivot.


Now for the pump cover assembly.
In the ZIP kit there is some small aluminum balls and a drill bit.


They say to punch the ball into this cup plug. It takes a bit of effort, but it does go in.


Once the ball was in, I used a automatic center punch to stake the cup so the ball can't leave, per the instructions.


Then, drill a hole at about 45 degrees from the corner of the cup plug to the adjacent cavity. The drill bit was so tiny! I was afraid to break it. Fortunately it survived. Cleaned out all the debris with compressed air.


The ZIP kit included a new spool valve and a booster valve.


Original booster valve, ZIP kit valve, and the Line booster kit valve. The original and ZIP kit valves both measured .450" the Line Booster kit valve measured .475". So there is a little improvement there. The line booster kid also included a stiffer spring for the main line pressure spool.


Once I had that done. I checked each spool, making sure they don't hang up, they aren't worn. All checked out good. So the pump cover assembly goes in.
One thing that is absolutely critical, is that the pump cover and the bell housing are exactly concentric. There is a tool specifically designed to align the two parts. but its very expensive and I'm very lazy. I put the screws in and carefully nudged the pump cover into exact alignment with the bellhousing. I checked in as many ways possible to make sure it was exactly lined up and torqued all the bolts in sequence to 97 in-lb.


At this point the bellhousing and pump assembly are complete.

Next up? 1-2-3-4 / 3-5-Reverse drum clutch assembly.
 

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Discussion Starter #15
Onward to the 1-2-3-4 / 3-5-R Drum.

One thing that is interesting about the design of the 6LX0 series, is that any clutches that rotate, naturally have a spring to retract the pistons. However, the spring is in a cavity that they feed low pressure fluid into. This is to combat the hydraulic pressure created when the clutch housings spin fast, that causes the pistons to apply when they shouldn't. Putting fluid on the spring side balances the pressure, they call it compensation. But, it does mean that there are a bunch more seals, and several more components.

The drum:



It takes all of 10 seconds to pop the first snap ring, dump out the clutches, and pop the second snap ring and dump them out.


Next, we have to remove the pistons.
I used some 3 and 4" sewage couplers to make a simple piston compressor.


Fish out the snap ring


Remove all the pistons, There are a lot of parts due to the compensation cavities


Remove all the seals from the pistons and the inside of the drum. There are quite a few.


3-5-R Piston, at the very back. It has a groove around the edge that pushes a cage that is inside of the 1-2-3-4 clutch pack to reach the 3-5-R clutches.


I replaced the seals on the piston and put in the return spring, slipped them into the 3-5-R compensation housing as well as replaced the seals on the inside of the drum.


The next thing is the 1-2-3-4 piston. The original is known to crack. Fortunately GM sells a stronger cast piston in later models, Also Sonnax makes a billet piston. I got the billet piston.


1-2-3-4 Return Spring


Then there is the 1-2-3-4 compensation dam (piston). Back in the press to install the snap ring.


After soaking the 1-2-3-4 clutches in ATF. I loaded them in. Waved spring, steel, clutch friction, steel and so on. the last clutch friction goes in, and the thick backer, followed by the snap ring. 1-2-3-4 Done. The snap ring groove, has a spot that doesn't have a groove. That is where the snap ring gap must go. I also like to make sure that the blank spot is between the 1-2-3-4 clutch Steel gaps. Exactly like this


This cage slips right past the 1-2-3-4 clutch steels, and the snap ring. It slips into the groove on the 3-5-R piston.


Next, waved plate, then the loading order is exactly the same as it was for the 1-2-3-4 set. But, this time the gap on the snap ring goes 180 degrees from the location of the 1-2-3-4 snap ring.


I put the new seals on the back side of the stator shaft and loaded the drum in place to check with air pressure. I put the air right into the holes on the bottom of the pump. Started off with 40 PSI on my compressor. The pistons wouldn't budge. I upped it a few times till I was at 100 PSI. Finally the pistons were applying. Reducing the pressure at all would cause the pistons to retract again. This is a problem. Granted, It is air and it leaks out easily, I realized just how bad it leaks.

I knew that in mid 2009, GM changed the design of the seals between the drum and the support. They found that the original design leaked, they didn't have enough outward tension, and that the fact that they were allowed to spin with the drum caused them to wear down as well. This caused all kinds of issues with the 2-3 shift.

So in mid 2009, they revised the design. They added backing O-rings to press the seals outward toward the drum, and added notches for the seals to lock into so they wouldn't spin. The change in design requires you to change the entire pump cover housing with the stator/drum support. You could do it for ~$170. But I've got a lathe, and a bit of creativity.


I used a modified parting tool to deepen the .107" wide grooves to 0.159" below the surface.


Then I turned the parting blade sideways and actually broached the notches with the lathe, took off about .005" per pass. It wasn't long before all the notches were cut.


Then I put the backing O-rings went in, followed by the seals.


I re-tested the drum pistons on the pump seals. Applying 60 PSI of air would push the pistons easily. I'd stop applying air and the pistons would stay applied for 4-6 seconds. That is a hell of an improvement!

I bolted the pump cover back on, and the 1-2-3-4 Drum is DONE.
 

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This is totally awesome! You have some serious skills.... and patience. I barely have the patience to read about everything you did let alone try to tackle a trans build like that. Props to you man! Can't wait to see the results!!
 
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Discussion Starter #17
4-5-6 Clutch!

I actually DON'T ever change the one piece rings on turbine shafts. They never go bad, and they require a few different special tools to replace them. An expander, a protector, and a shrinking (? or whatever) tool. So forget that nonsense.

This clutch assembly was pretty straight forward. No drama. But, almost the entire actuating assembly was replaced with the Sonnax 4-5-6 clutch kit.
From the Sonnax web site, showing what they changed.


Long story short, they shortened the piston a little, and stuffed a stiffening apply ring to the bottom of the clutch, and thickened the top ring. This was all done to keep the clutches flat under higher loads. If you look at the cross section, the original piston pushed near the outer edge of the wave ring, and only had a standard steel as the bottom clutch surface. When clutch apply loads are pretty high, they can deflect and "Cone" under the pressure. Less of a potential problem with this kit. This clutch is the smallest clutch pack within the transmission. But, it is also one that runs at engine torque only. So at least they stuffed 7 clutches into it. Most of the other clutches run at about ~1.5 times engine torque.

I used my press and spacer to compress the dam, pop out the snap ring. Once released, and the piston dam (Compensation dam) came off, there is the return spring.


I removed the piston and all the other goods and replaced them with the Sonnax parts. Pressed it back in, put the snap ring back on. Then it was the new bottom ring, the wave plate, Steel, clutch X7, then the new top ring and the snap ring. Done.

I loaded it into the pump assembly and applied air pressure to test it. It passed. Good.

Next up, the center support housing.

The center support housing contains two very large diameter clutches. Probably the biggest clutches I've ever seen in a transmission. In the front, the 2-6 clutch, this one stops the drum that normally is driven by the 3-5-R clutches. So... Never turn on those clutches at the same time! so you can see that the transmission transitions twice between them during the normal gear pattern.
After I popped the clutch snap ring and removed the clutches and steels, I encountered something different than I'm used to. There is a snap ring that is retaining the 2-6 piston return spring.

Removing the snap ring was easy. I replaced the piston with a new one, and put the spring back in and let me say, it was a royal **** in the ***. I don't even want to begin to describe how much it sucked to get that spring compressed all the way around while slipping in the snap ring. There is a special tool for this and I'm not worthy. I replaced the clutches and begrudgingly moved on with my life.

In the back of the center support housing is the Low-Reverse clutch. It stops the rear planetary middle housing. Also, stuffed into the low reverse housing, is the 1st gear sprag. It engages as part of first gear, and freewheels for all other gears. The Low reverse clutch is just to make the sprag effectively lock in both directions. Interestingly... The low reverse clutch actually has two apply areas on the piston. Neutral and Low use the smaller area, Reverse uses the entire piston, including both apply areas. They do this to decrease the amount of force applied in low to limit how much braking the transmission can do. The clutch will slip if excessive braking torque is applied. They don't want you spinning out when the rear wheels over brake via transmission.
I checked out the parts, reloaded them and changed those clutches. When checking the sprag, they are notorious for being easy to install backwards. This would cause some severe problems. I imagine the transmission would work in first and reverse and probably would freewheel just before the transmission shifts into second which would lock up the whole transmission. That would suck.
Not going to go into the details because its the same thing as all the other clutches.

The last parts are just the output planetary sets. If there is no visible damage, there is nothing to replace. They are incredibly heavily built. The output shaft assembly is 17 lbs. The planetary set is 19 lbs. So just the output assembly is 36 lbs. Fricken heavy!

As I was rebuilding the parts, I was stacking them on the bellhousing/pump assembly. Kind of neat to see how it all goes together.


Next up, loading the mechanicals.
 

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Discussion Starter #18
Loading the case time!

First, start with the Gutted case. 19 lbs.


I placed the empty case on top of an old wheel rim, so that the output shaft can protrude when I drop that in.
This transmission has torrington style thrust bearings throughout, and they are each completley unique, none of them will interchange fortunately. They either fit tightly over or into the housings they seperate. There is a bearing beteen pretty much every assembly you load into the case.
So, first I drop in a bearing, then the 17 lb output shaft and outer planet assembly.


Then another bearing, then the planetary carrier, have to spin them a bit to get it to slip in.


Then another bearing, and the center support goes in, big ports facing the pan. Making sure that the assembly keys into the carrier below. Should see the entire snap ring groove around the face of the housing if it is in all the way.


Then there is the almost comically huge snap ring which I was showing as I installed it in the previous picture.


The snap ring goes in with the taper facing you. This way when it expands it will force the center support housing hard down into the case.
I used a modified welding vice clamp to clamp the ring, but seriously, it's probably a bit dangerous to try to load this ring in even with the proper tools. Luckily I've survived.


Then another bearing, and then the 2-6/3-5-R shell. Spin the shell and make sure that it engages each of the 2-6 clutches, it will make a distinct clunk when it hits the bottom bearing.


Another Bearing, then the 1-2-3-4 shell.


Then another bearing. Surprise.
Then the 4-5-6 shaft slips right through the center of the shells, and engages all the way down into the planetary carrier.


Another bearing!
Now we load the turbine shaft and 4-5-6 clutch assembly. Making sure you rotate it and get it to pop all the way through the clutch plates till it hits the bearing. Again, the distinctly different clunk.
Why not throw another bearing in while we're at it. This one is to support the center pinion.


Then we drop in the planetary assembly, Spline facing up.


This thrust washer goes on the underside of the planetary, a little bit of grease was enough to keep the thrust washer in place while dropping the planetary assembly in place.


Then the gear goes in, its symmetrical, so either way will work. Preferably you should put it in the same way its always been used if you can remember which way that was.


This is the one time I don't install another bearing.
This time we drop in the 1-2-3-4 / 3-5-R drum. Now this is interesting because of just how many things that must key in, in order to be sure its fully installed. There is a tool they make to rotate and hold the drum. But I did it without. I kept checking through the side of the drum to make sure that I could see that the last clutches were engaged. It's pretty hard to tell otherwise. Lots of wiggling and turning.


Time to put the finishing touches on. I replaced the seal around the pump bellhousing assembly, lubed it up with some ATF and used some grease to secure the thrust washer to the face of the pump. Then it was a matter of lowering it very carefully onto the transmission. It slipped in with just a little bit of wiggle. Had to rotate it to clear the vent tube. It slipped in all the way to flush, which is a good indication that all the clutches are fully seated. Forgot the pic, but you get the idea.
I placed the bellhousing bolts in, and tightened them up to 53 lb-ft. I have to admit it felt a bit excessive, but thats what the manual said.

At this point the whole stack is done.

Next up, Valve body.
 

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Discussion Starter #19
With the valve body split, its time to focus on the upgrades.
This is where Sonnax went over and beyond to make improvements, all of which are contained in the 6L45-6L90 ZIP kit.


They made some pretty dramatic changes to some of the valves, particularly the TCC control. But most of the changes were to address leakage. Surprisingly, there are a lot of places that receive pressurized ATF that ARE NOT sealed, or even really all that tight of a fit. They use round aluminum plugs on the end of most valve spools to keep the pressure where it needs to be. They have no seal, and likely leak a bit. Sonnax fixed this issue by making bore plugs that O-rings can fit around, this will definitely eliminate that leak. In 4 places even.


If you are interested in exactly what has to be done to install the entire kit, have a look here:
http://d2q1ebiag300ih.cloudfront.net/uploads/part/instructions/3505/6L45-6L90-ZIP-IN_D.pdf?v=1492107819

I didn't know this at the time, the Master rebuild kit came with several paper gaskets for the separator plate. However, the separator plate between the valve bodies has the gaskets are bonded to it from the factory. So the included gaskets in the rebuild kit are absolutely useless. You just replace the whole plate. I found one with the updated part number new for $12, kind of a no-brainer.


I laid the two plates over each other and very carefully inspected them to see if I could spot the differences from both sides. As far as I could tell, there was only one difference.


Looking at the schematics, it looks like it slows down the spool that is used to amplify the control fluid signal to the 4-5-6 clutch control valve. So it probably slows down the 4-5-6 clutch response a bit if I'm reading it correctly. No big deal.

Also, the rebuild kit came with white check balls, they are a hard plastic. They are identical to the old ones I removed. But the ZIP kit comes with brown "Torlon" check balls. They are more like a hard rubber consistency. This is a common upgrade for all transmissions. Don't know why they don't just use these from the factory.


Make absolutely sure they are where they need to be


New spacer plate in place


and I can close up the valve body assembly following the instruction manual, many of the bolts get torqued down.

The TEHCM isn't really serviceable, its either good or bad. The only thing I could do to it is replace the pressure switch diaphragms, and clean the switches while I'm in there, then replace the debris screen. Again, Sonnax makes a pressure switch rebuild kit for the TEHCM.


I'm not really going to get into that, but I can say there is a fairly useful video on YouTube that shows how to do the rebuild, and test it.

I also replaced the old IMS (PRNDL, Range) switch. There was an updated part number, so I got that and replaced it. I reinstalled the TEHCM, and torqued all the bolts, and reinstalled the speed sensors. The valve body is almost complete


One last thing from the ZIP kit, the body seals on the center support housing to the valve body. Bit of an interesting modification really, especially since it effectively locks the center support housing into the transmission, and makes it pretty difficult to remove.
It came with these sleeves that needed to be hammered into the center support, and into the valve body. The threaded ones go into the center support, as they would need to be removed to disassemble the transmission in the future


Tapped, OK, hammered these into the center support, making sure these are the threaded ones


Did the same on the valve body, non threaded


Then as per the instructions, I placed the seal on the transmission, and placed the two 1/4" length springs into the outer two holes, and left the center ones empty.


I put the other seals onto the valve body and installed it. I also re-assembled the range valve, the rooster comb, the shift select shaft and parking pawl actuator, and put the filter on.


Then the gasket and pan. The gasket on these transmission is 100% reusable, which is great!

Next up, finishing touches and misc. preparations for the install.
 
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