I apologize if this is a stupid question, but I have a question about my rear end and upgrading it. I have a 1989 RS 5 speed V6 and from what I know I have 3.42 gears (correct me if I am wrong). I have a parts car thats a 1984 Z28 Automatic V8 which I believe has 3.42 gears as well. Would one be better or different than the other? Are they both Posi?

Thank you

 

a v6 rear end and a v8 rear end are going to have different gears, im not sure what the v8 gears are but their different than the v6 rear i call tell you that forsure
their is more redustion on a v8 rear end, to help explain:
if you have a v8 running on a v6 rear end
and he has a v8 on a v8 rear end
youd win the race because there is less reduction in a v6 rear end
companies do this so you can put more power from the lesser engine to the ground so your still fast

now if you could help me... how do u post a new thread???

 

Whenever you are in the exact board you want to post to just go towards the bottom and there will be a "New Thread" button bottom left corner.

 

V8's and V6's run the same rear ends (Check the following link for spline count and limited slip info). Disc brakes and limited slip might make one more desirable than the other, but then there's the combination valve and parking brake issues to consider. The following link will provide some insight into the aforementioned matters:

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

 

Who ever you heard this from is on crack.

 

Your V6 car is probably not posi, but seeing your from PA it could be (snow). The 84Z is probably not (I used those words again) a 3:42 gear. One sure way to find out is check. To check for posi, jack rear up so both wheels in the air. Have manual car in gear, auto car in park. Then try to turn one rear wheel. If the wheel turns easy, and the other wheel turns in the opposite direction, its not a posi. If you can't turn the wheel, put the car in neutral, get a buddy and try to turn the wheels in opposite directions. If you can't it's a posi. Best way to check ratio(gear) is to remove housing cover, count the teeth on the ring gear then the pinion. Divide the ring gear number by the pinion = ratio. A question is not stupid if you don't know. Now you'll never have to ask that particular question again. Only difference should be axles( 84=26 spline, 89=28 spline) and maybe brakes( drum or disc)If both are posi and 3:42. Hope this helps, Dean.

 

89 is the transition year. A few 28-splines may have crept in late in the year, but most seem to be 26. Check the FAQ posted above for more info, should you be interested.

JamesC

 

I didn,'t mean to give any bad info, but i have a rear out of an 89 that is a 28 spline. Got it at the JY, didn't look at the build date. It may have not even been the origional. It had a broken spider gear. I got it really cheap. I only wanted it to make a housing jig. Come to think of it, it may have not even been an 89. JY owner said thats what it was. Dean