question about gear swap

[Boggin]

i was talkin to my buddy the other day while he was tearing apart a rear diff out of a big rig at his garage, he told me if i wanted a new gear set that i could take out everything from my old diff and mark every shim where it came from and what not and put the new gears in with everything the same way it came out and it would work, told me he done a few of his firebirds and it worked fine. can i do this with my d35 and 7.5? if so it would be the cats ass..

thanks!

 

[RangerSVT]

Usually, it works out this way, but you still need to check for backlash as well as gear contact...
SVT

 

[Boggin]

yeah, im fine with checking gear contact. still not positive on the backlash though

 

[RangerSVT]

You need a dial indicator to check that
SVT

 

[Boggin]

Yeah ill search up my garage for one and read up on it and give it a go on a spare set of gears and see if it works.. thanks man

 

[4x4junkie]

Backlash is the amount of "space" or lash between the gear teeth. Typically it'll be between .008-.015" on these axles. You need a dial indicator w/magnetic base to measure it.



Doing it like you say will usually get you pretty close, but you cannot count on it being dead-on..

Check both the gear contact pattern and backlash before you disassemble anything, and be sure everything's reset to the same when you reassemble it. Expect to have to make some minor shim adjustments afterward (both pinion depth and carrier bearing shims).

Edit:
Dang... fast-moving thread here lol

 

[Boggin]

thanks guys! so even if i never drove above 80kmh (nowhere near highway speeds) and just a beater for around town and only need it to last a year or so, i still need that backlash to be dead on right

 

[4x4junkie]

Yep.

If the tooth contact isn't correct, the teeth can break off and/or become badly scored.