Im trying to find ring and pinion sets for a 91 Rs and I keep seeing 7.5 27 splines . Is mine a 7.625 or a 7.5 and mine is 28 and not 27 spline right?

 

It doesn't matter as long as you are not replacing the carrier, our rears are 7 5/8 or 7.625. But usally the gears say they are made for 7.5 AND 7.625. Should bolt right up if you get them for the right series carrier and know how to set up a rear end.

 

Demetri, you're still asking this same question?

GM changed from a 7.5" ring to a 7.625" ring sometime in the mid-eighties. As Phoenix305 said, either will fit your carrier. Just get an aftermarket set like Richmond, http://www.jegs.com/cgi-bin/ncommerc...61&prmenbr=361. If you are staying with your stock carrier, you will need a 2-series (thick) version.

Your '90 RS has 28 spline axles as GM changed over mid-year 1989. The 27 spline count you mentioned is the gear pinion's spline count.

HTH

 

So thats what I look for? 27 spline pinion? 200$ is a little pricey but I guess these are the best right?

 

you won't have a choice on pinion spline for a 10 bolt. i don't think you have a very good handle on what spline is what, 28 or 26 is the axles, the pinion never changed. not sure but i'd just about bet the 9 bolt used same splines so the yoke interchanges.

 

All I need to know is what to look for.

 

Here, plain and simple get what ever gear ratio you need, but make sure its for a series 2 carrier and a 7.5 and 7.625 rear. I wouldn't go with richmond gears unless your planning on using them for drag race only. They can handel alot but they whine more than other brands. I went with motive gears.

 

why not 3 series

 

Because you have a 2 series carrier. You need the thicker ring gear. 3:23 gears and up from factory use a 3 series carrier. In case you don't know, the carrier is the differential.

 

the posi that im buying comes with a differential doesnt it?




EDIT: Actually why don't you just tell me what to buy. (no aubern)i just want a posi with a 3.42 gear (or tell me if i should go higher)

 

a posi is a differential

you need:

a carrier also called a differential, or posi (if it's a posi)

a gear set in the ratio of your choice, it'll also have to fit the carrier, either by being the correct part or by being a part made to adapt nonstandard ratios to carriers they didn't come from the factory with, or by using a ring gear shim.

a modified cross pin if you go 4:56 and maybe another ratio or two, but i tihnk it's 4:56 only

an install kit

oil

posi additive, gm only

someone to install it for you

 

so this
https://www.justdifferentials.com/st...cat=172&page=1

and this

https://www.justdifferentials.com/st...cat=381&page=1

and this

http://www.jegs.com/cgi-bin/ncommerc...17&prmenbr=361

and this

http://www.jegs.com/cgi-bin/ncommerc...19&prmenbr=361

and this

http://www.jegs.com/cgi-bin/ncommerc...48&prmenbr=361



That will all work right?

 

bump..