sorry im sure this has been covered on here a hundred times , but i could not find a thread that answered my questions, so if i swapped my non zr2 front diff with a zr2 one , will i need to replace the gears in my rear diff too? has anybody done this already?

 

what is the reason you want to swap diffs. They are both the same unless it is an iron one. You would only have to swap gears if your rear diff isnt 3.73s

 

im pretty sure that my diff is messed up internally and i dont know much about tearing down a front diff and rebuilding it, so i thought id locate an iron one to replace it, i also think i have the 3.42s but im not 100% positive.

 

which we all know only came in the manual trans trucks.

get your VIN checked @ a dealer.

i had an awsome site for VIN decoding (i think it wa for GM vehicles only) but i can't seem to find it anywhere. (thought i had book marked the site, but i don't know.....................)

 

GU6, GU8 etc should be your gearing ratio in the glove box. If oyu install a front diff with the same gear ration your fine, if you swap in one with a different gear ratio you need to swap the rear diff ratio to match, or swap the gears in the new front diff to match. Either way you need to match your front and rear diff rations.

PS, I dont think a ZR2 front diff will fit. The ZR2 has a wider frame and some other frame differences.

In hte long run, your going to be money ahead rebuilding your current or replacing with a suitable replacement ( same gearing). Your salvage yard will be albe to tell you what will swap in as a direct replacement.

 

thanks for the info everyone, i just thought if i had to replace it i would upgrade and i heard that the zr2 iron front diff was the best and would bolt right in