[Jvert18]

Looking for a 3.73 rear diff. Where's the best place in the US to search? Prefer the entire cradle.

[L78toLT1]

I'd recommend just swapping the diff vs. The entire cradle, unless you're picking up a used cradle assy with diff, axles, knuckle, links and all. If you do get the entire assembly, the SS rear brakes are different and not 100% compatible due to differeces in the parking brake. You may be able to install your knuckle and brakes on the SS cradle but that is a bigger pita than just swapping the diff.

[StPeteHyper2.0]

Just to back this up. I swapped to 3.73 diff and swapped my rear knuckles to SS with inner parking brake. I did 15" conversion on SS knuckles with BMR suspension. Stock cradle and axles. I installed an aftermarket estopp brake kit attached to the SS parking cables that I made brackets for. Tho I have rode around 2 months plus without the parking brake. Only real downfall is the service parking brake light on the dash I haven't figured out how to turn off yet.

[StPeteHyper2.0]

..and you can find the 3.73 diff new on ebay shipped for $700ish. Just have to cross match part numbers to get the right one

[cmitchell17]

Originally Posted by StPeteHyper2.0

..and you can find the 3.73 diff new on ebay shipped for $700ish. Just have to cross match part numbers to get the right one

Do you feel like the 3.73 is too low of a gear? I mean with the 8L90 first gear it seems the trans already has trouble trying to shift fast enough so it short shifts (this may not actually be why this happens but its suspected it is). I think I remember some other people who swapped to the 3.73s had WOT shift problems and trying to get the TCM to do what we want is the hard part.

I mean I think always no matter what you should gear as low as possible until you hit your limit of traction always no matter what.

[StPeteHyper2.0]

Originally Posted by cmitchell17

Do you feel like the 3.73 is too low of a gear? I mean with the 8L90 first gear it seems the trans already has trouble trying to shift fast enough so it short shifts (this may not actually be why this happens but its suspected it is). I think I remember some other people who swapped to the 3.73s had WOT shift problems and trying to get the TCM to do what we want is the hard part.

I mean I think always no matter what you should gear as low as possible until you hit your limit of traction always no matter what.

I can't really answer that. I have a manual 2.0. Came with 3.27 LSD. The 6speed with 3.73 works great. I don't know how the 8speed would feel and tcm issues. I only know 1 other 2.0 auto 8speed that has 3.73 diff and that's Allen's ZZP camaro that ran 10s, strictly a drag car. No one I know daily drives that setup. V6 autos are only one that has 2.77 diff and many upgrade to 3.27 lsd, but 3.73 would be big change from 2.77.

[Jvert18]

Originally Posted by StPeteHyper2.0

..and you can find the 3.73 diff new on ebay shipped for $700ish. Just have to cross match part numbers to get the right one

Thanks for the info, I'll check it out!

[Jvert18]

Originally Posted by cmitchell17

Do you feel like the 3.73 is too low of a gear? I mean with the 8L90 first gear it seems the trans already has trouble trying to shift fast enough so it short shifts (this may not actually be why this happens but its suspected it is). I think I remember some other people who swapped to the 3.73s had WOT shift problems and trying to get the TCM to do what we want is the hard part.

I mean I think always no matter what you should gear as low as possible until you hit your limit of traction always no matter what.

I have the M6 as well.....

[cmitchell17]

I just bought a 3.73 and I paid dearly for it haha. In my opinion, as long as you aren't concerned about the .25mpg you will lose you should always gear to the lowest gear you possibly can if you want to accelerate the fastest period. F = ma is always true no matter what. The only limitations being if you have reached your traction limit (stock SS's have reached their traction limit) or you need to hit a certain speed. With the 8L90 gearing with 3.73 rear gear, you would still be able to achieve the theoretical top speed.

So I may have to take all that back, after having the 3.73s for a week or so, I haven't noticed any improvements. It also has broken my shift points and we don't have access to the proper tables we need to fix it in HP Tuners, it is making the lower gears at part throttle hang and shift late and is really annoying driving around town.