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TrailblazerSS
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Discussion Starter · #1 ·
I tried searching the rear-end forum with "4.56" as the key word. Didn't find anything so I apologize if this is a repost. Has anyone ever done 4.56 gears? I have an AWD and am having front diff rear sealed under powertrain warranty and was thinking about have them install 4.56s. Just wondering what kind of performance gains are seen as well as what kind of MPG changes ppl have seen. I tow a lot so putting in a decent stall isn't really an option for me. Also do you have to retune the trans shift points, obv the speedo would need to be retuned too right? Any info is appreciated, thanks.
 

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TrailblazerSS
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Damn those are some pretty stout gears, why going bigger have you gone with smaller rims and tires first not saying you cant but the stock 4:10's are pretty nice, but its your choice there are some threads here and there of people going or thinking of going bigger but dont remember the search function doesnt work right so dont use it. Just go the the home link and then scroll down and look for your topic.
 

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Trailblazer SS
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I have 4.56 and they fucking RIP. My mpg dropped a blistering 1mpg! They were worth it!
 

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Trailblazer SS
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Yet...... Lol
 

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TrailblazerSS
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Discussion Starter · #6 ·
No available yet? Damn alright, thx gents!
 

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2008 Saab 97x Aero
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4.56s with 29"-30" tire would be bada$$, use dennys driveshaft to estimate rpms

My buddy has 4.56s with 6l90e and said the 6 speed really accents the 4.56s!! I think hes sneakin a snail in because said hes going 3.73 now!!

Youtube chevrolade1 youlll see his ride
 

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2007 TBSS AWD
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4.56s with 29"-30" tire would be bada$$, use dennys driveshaft to estimate rpms

My buddy has 4.56s with 6l90e and said the 6 speed really accents the 4.56s!! I think hes sneakin a snail in because said hes going 3.73 now!!

Youtube chevrolade1 youlll see his ride
4.56 is steep for the 1st gear in that 6 speed.
 

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SSR & TBSS
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I have 4.56s in my SSR and can tell a big difference between it and the 4.10s in the TBSS. The SSR feels 10 times lighter than the TBSS with this change. Lost 1 MPG on mileage with the change to 4.56... (but the SSR still gets better mileage than the TBSS). The trans shift points were re-scaled using HP tuners although I had to have someone (Bryan Herter at PCM4Less) with LS1(LS2)Edit fix the speedo settings since HP Tuners has a bug and doesn't set the right speedo parameters.
 

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2008 TB SS AWD 3SS
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The 4.56 was probably one of my favorite mods, especially considering how cheap it was. I run a 28" tire... 275/50-17 M&H. My mpg didn't change at all.
Even on the highway at like 75?

These things already get crap for mileage (not complaining, just stating again) so Ive been debating a set of 3.42s for a while. Just a PITA to deal with the front diff, plus 2 sets of gears offsets any $$ savings for a long time.

4.02:1 first, dang. That with 4.56s would be a hardcore stump puller off the line, crazy 60s if you run DRs and it hooks right. :muahaha:
 

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2007 TBSS AWD
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Even on the highway at like 75?

These things already get crap for mileage (not complaining, just stating again) so Ive been debating a set of 3.42s for a while. Just a PITA to deal with the front diff, plus 2 sets of gears offsets any $$ savings for a long time.

4.02:1 first, dang. That with 4.56s would be a hardcore stump puller off the line, crazy 60s if you run DRs and it hooks right. :muahaha:
The 4.02 first is in the 6L80/90E

Our 4L60/65/70Es have a 3.06 first
 

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TrailblazerSS
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Even on the highway at like 75?

These things already get crap for mileage (not complaining, just stating again) so Ive been debating a set of 3.42s for a while. Just a PITA to deal with the front diff, plus 2 sets of gears offsets any $$ savings for a long time.
I normally cruise at 65-70, but yes. I have a gutted 2wd, but even with the 4.56 gear, 3600 or 4000 converter, and a baby cam, I manage 12/16, and it's running pig rich.
 

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I can't go over 85 for a long period of time or my oil temp gets a lil high for my liking
 
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