My 2.73's are bogus. I want something more performance oriented. My buddy who has a '90 IROC is buying a Moser 9". He has 3.73's that he said he would give me. My question is will his posi fit my rear end? I was told I have 26 spline axles and his car has 28. The reason he's switching rears besides the obvious, is that his axles might be warped. He hit a curb at 100kmh one day and totally messed his car. Once you pass 3200rpm, the rear end has this CRAZY vibration. He's had the gears checked out and they seem to be fine. Only other thing we can think of is the axles so taking those would be out of the question. Any thoughts?

 

Well, im not sure about the splines, but I think they should be the same.
1 other thing is your going to have to upgrade to a series 3 carrier. Now you have a series 2.

 

If your carrier is a 2 series (and the donar is a 3 series), you might be able to use a ring gear spacer to install the 3.73's. Contact the folks at http://www.ring-pinion.com for some advice. They can also help you with an installation kit, etc. Also, ask them about using a solid pinion spacer instead of a crush sleeve.

Good luck

 

Thanks guys!

 

facts;

88 was the year spline count changed from 26 to 28

2.73 is 3 series carrier

3.73 is 4 series carrier

you will need the 4 series carrier or preferablt entire axle assembly intact and not taken apart or you will have a nightmare

ring gear spacer isnt a real good approach but will work but you better know how to or know someone who darn well knows how to properly set up carriers and gears or you will hve a disaster in short order

good luck

 

Ummm, no...

Late 89 was the 26- to 28-spline changeover; the vast majority of 89s are still 26, but a few got 28; and nearly all 90s got 28

2.73 is on a 2 series carrier. (2.xx) That series of carrier is used with 3.08 and lower numbers.

3.73 is on a 3 series carrier. 3.23 and higher are on the 3 series.

There is no 4 series in this model of rear end.

The ring gear spacer works fine, as long as the installer knows what they're doing.

If your 2.73 rear doesn't have posi, you might as well buy a 3 series carrier, and put that in along with your gear swap. I'd suggest this one.

 

4 series? lol

Yeah I was thinking of using the Eaton unit. I also was going to take my buddies '90 10 bolt and use that as my platform for the build. New posi, new axles etc. Thanks for the info guys, appreciate it!

PS. Is it possible to put drum brakes on a disc rear? He's keeping his Disc stuff so for right now, I'll hang onto my Aluminum drums.

 

No, not easily anyway... the mounting flange on the end of the axle tubes is MUCH larger for drums than discs. You can go the other way, with some effort; but not that way.

I have the Eaton in my car, seems to do pretty well. I like it alot better than the Auburn High-Perf I had before it, that tore up.