I was just curious, I was running the RPO codes on the 85 Trans Am that I have, and it says that the axle ratio is a 3.27:1, but I don't see that particular gearing on the tech data. Is this a common occurance? The car is an LB9, and there are only two listed under that motor, 3.23 and a 3.42. Just curious if this was normal......

 

The 3:27 axle ratio means you have the BW 9-bolt rear. That was the high performace axle offered on the early Firebirds and in 1987 on the Camaro's. They came in 2:77, 3:27 and 3:45 . A stronger rear then the standard 10-bolt.

 

So you mean if I have the BW rear in my car, I actually have a 3.45 rear instead of a 3.42 like my RPO's indicate?

 

I dont think the BW's were in the 90's.Am I wrong?

 

Brett
All you have with your 90 LB9 is a 10-bolt and whatever your RPO code tell you what ratio it is.

 

I looked up some previous postings by a BW fan ........

Here are some facts about your axel:

According to Hi Performance Pontiac, Dec 84, the Borg-Warner 3.27 axel was a "true posi (as opposed to an Eaton Locker)"

It was built by in Austrailia.

Externaly they are the same as previous axles but inside is 7-3/4 ring gear and 28 spline axels.

The extra duribility comes from a four pin differential, the weak link in rears are the ones with only 2 pinions.

Elimination of the C clips and the use of tappered roller bearings at the wheels are additional strong points.

Is stronger than the chevy 26 spline, 7-5/8 ring gear.

Is stronger than a 8-1/2" Dana 44 !!

Why? The Woodard Schedule......


The Woodward Schedule was a test where Pontiac launched the car by side stepping the clutch at 4000+ RPM and power shifting thru every gear at redline.

They ran about 30 axles through 200 Woodward tests without a single failure.

The Danas broke in this test.

I would have to conclude that there is no better rear end in the 3rd gen than the one you have, I'm a little biased

 

what axle got the 3.23 ratio ? 84 Z28 700r4 305 LG4*

 

For those of us with this wonderful differential that is no longer made...a guy named Miles in Minnesota purchased the production rights and supplies parts for this rear. His website is located here. He has a very good reputation and is very helpful. A search of the forums at Minnesota F-Body Club's website will prove this out. Miles posts there frequently. Good luck and happy motoring!!
Scott

 

on my stock 1988 formula 350 it had the borg wagner 9 bolt rear end with the 3.27 posi...

 

Awesome, THANKS