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Discussion Starter #1
My trans was rebuilt with parts that greg recommended including one of his 2600 stall coverters. At very low rpm, there is a vibration from the trans. My builder advised for me to put the trans in neutral and slowly raise the RPM's. The vibration gets a little worse until about 3000 rpm. Do i need to worry about this vibration? I was told that the converter may be slightly out of balance? Does that make sense? Any other suggestions?
 

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Every converter we build is balanced to zero grams on a computer balancer, and every converter is built one at a time so no step in the process is overlooked. If you believe the converter to be out of balance I will happily send you another to try, but before going to that, I would be sure there is no part of the exhaust or any other engine component touching any crossmember, frame or body component. I have seen even a dipstick tube against a firewall set up a vibration in a vehicle. Check it out and let me know how we can be of help to you.
 

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Discussion Starter #4
Thanks Greg, I am sure your converter is fine!! We will check to see if anything is touching but it feels like its internal to the trans. The installer did mention when he shimmed the trans that he tacked the shims to the converter....... I hope that isnt it... Anyone want to dare to make an opinion?

The trans builder is a great local builder who has built hundreds of trans, including one for my race car. I have trust in him.

Any suggestions that I can give him would be appreciated. We put the following parts in the trans
8 clutch HP 3-4 clutch packs
High energy 2-4 band
beast sun shell kit
transgo shift kit (we did not use the race option with the kit)
corvette 2nd gear servo
billet 4th gear servo assembly
3rd gear relief valve assembly
wide reaction sun gear bushings
standard rebuild kit

This is an AWD truck... thanks guys
 

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This vibration happens when standing and revving, or are you driving?
 

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Were the shims TIG'd or MIG'd to the converter? Are you sure they are exactly the same thickness right down to the .001"? A very small runout can cause a lot of issues, now and later.
 

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Discussion Starter #8
It happens while driving slowly at low RPM'S. Its worse when someone suggested to put the truck in nuetral and see if it still vibrations while standing.
 

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He tacked shims to the converter? this could be a problem...I have never found a way to induce a vibration by building a trans so I doubt it is anything internal, Check the things I posted before but I am now suspecting these welded shims could be at issue.
 

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I am guessing its the welds throwing it off.
 

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If I could make a suggestion.
Take the TC bolts out and clock the converter one lug and put the bolts back in and see if the vibration goes away.
I work at a trans shop and had this issue with my TBSS here a little while back and it fixed it completely.
Now if the vibration was only when driving I would say take the drive shafts loose from the yolks on the diff and clock them 180*you would be surprised how often drive shafts cause vibration issues.We mark everyone we take out so it is indexed just as it was when we go back together.
 

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I am guessing its the welds throwing it off.
I agree 110% Ricky Bobby. It they were just tacked in equal spots it wouldn't be an issue, but if one side it tacked and the other side had a "bead" or a gum ball it could cause a issue.

Another thing it could be is the spacers them self. If one is ticker then the other it would cause the verter to sit uneven and that would be a major issue.


If anything, those spacers should have been tacked onto the flywheel in equal spots, or a complete bead ran around them. Not the verter!

How many spacers where used? And what size?
 

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A 1/4" shim? That's way to fucking much! I don't even know how the bolts are grabbing anything. It should be 1/8" max!
 

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Discussion Starter #16
Correct me if I am wrong, the trans has to come out to remove the shims or even to clock the converter or is there enough room in the access panel?
 

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Correct me if I am wrong, the trans has to come out to remove the shims or even to clock the converter or is there enough room in the access panel?

No the trans doesn't need to come out normally, but since your spaces are welded on. Yours needs to come out.

I obviously don't know the combo - but why the fuck are there shims involved anyways?
You have to space the verter away from the flex-plate, to make sure the hub of the converter is far enough into the pump of the trans. I6 conveters don't need this, but any custom built one typically does.
 

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Not a good idea to tack shims on after it is balanced. Definitely could be the issue. The shims themselves could be off much less the weld.

Like mentioned, might want to try and rotate the converter on the flex-plate and hope. Good luck.

Chris
 

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I talked to the builder and installer on this truck today and he seems like a pretty knowledgable fellow. He explained that he put the lightest of tacks on the shims and that he used a ground and high quality shim, and only to shim the converter to what he felt was a proper depth. I think we should wait till we get the converter back and checked out before anyone throws him under the bus on this. Truth is there could be several reasons for a vibration and it is wrong to rush to judgement. I have been in this situation as both a customer and a builder and know what it feels like from either end.
 
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