Ok guys, I bought a 9 bolt not too long ago, and I didn't really know too much about them other than they were suppose to be strong. Anyway, the guy said he checked and it was 3.45's which when got it home and checked it was 2.77's. Last time I take somebodies word. My question is, what is the diiference between the series 2 and 3 carriers. I want a new set of gears, but all I here is I need the series 3. The rear came out of a 89 IROC. And another thing is, I think It may be getting loose, when I spin the tires sometimes it locks up, sometimes it doesn't. Does anyone else have this problem?

 

Here you go www.9bolt.com

The difference is the location of the ring gear relative to the pinion center line. Unfortunately, the 9 bolt carrier design does not allow for proper ring gear location and alignment when using a spacer. We are currently working on a solution for this problem and hope to have it readily available this later this fall.

Miles
Diff Solutions

 

How do I know which one I have? Did the series three come in the stock rearend?

 

2.77 & 3.08 = series 2
3.2x and up = series 3

Miles

 

What years did the 9 bolt rear come in our cars. Can you tell what rear you have from the RPO listings?

 

Sell that rear and get something else. And make sure it is a 3.27 and up this time so you don't waste your money and time. And don't go to 9bolt.com because he can't do anything for you and hes' to much money. for his price you can go and buy a good used rear.

 

9-bolts were optional in the 85-89 Trans Ams, and 87-89 IROC's. All 350's in those years have 9-bolts, either 2.77 or 3.27. The 3.45 ratio came in 5-speed cars with the G92 option. There is a 3.70 ratio that only came in 85-86 Trams Ams with the L69 engine and G92 option package, but they are really rare.

The RPO codes will be GUx for a 10-bolt rear and GWx for a 9-bolt rear. However, the 3.70 and 3.73 ratios RPO codes dont follow this pattern. The easiest way to tell is to count the number of bolts holding your rear end cover on.