Do TTA's use the 7.5 ten bolt, or the GN rear end?

[neat]

Which rear end is in the turbo TA's?

[Quiky One]

Neither...It's an Australian 9 bolt Borg Warner

Jason

[neat]

Wow, never heard of that one.

Is it any good? I'm really impressed with the stock rear in the T-type, it's much stronger than the rear was in my 99 Trans-Am. How do the 9 bolts hold up?

[Quick6'n'-K.C.]

I think they hold up fine till your beating on it hard into the high tens all the time.
They do make a little noise after you beat on them for a few years, but if its a weekend warrior, wait till it blows and a replacement is fairly cheap.

The 9 bolt was nothing special for the TTA, it was avail in standard production trans ams i believe all GTA's , 3:27 gears?

BW

[WS6]

This will answer all your questions about the BW 9 bolt, including all ratios available over it's life. The TTA only got the 3.27 ratio. TPI cars could have gotten other ratios based on displacement,A/C. trans type, etc.

Everything I know about 9-Bolt Rearends! - FAQ Board - Third Generation F-Body Message Boards

[Lynn D. Brown]

No, the Australian B&W on the TTA has a slightly larger ring gear than the GTA. If I remember, and I can look it up, the ring gear on the TTA is 7.785".

Not sure how it measures up to the the GN 8.5", but if it's all about ring gear size, it wouldn't be as strong. However the lower ratio of 3.29 should be easier on it than the 3.42 on the GN. One possible disadvantage is, I'm not aware that anyone offers a cast TA-type rear cover for it. Anybody know if anybody sells one ?

[WS6]

Interesting? I just went through an entire axle rebuild on the TTA, complete with ring and pinion ratio change and found no evidence from any supplier, including GM,of a larger ring gear other than 7.750, certainly I'm no expert on carriers, but seeing this one, it's a tough carrier!

[zerotta]

TTAs have the same Australian 9 bolts as IROCs and GTA/TA/Formulas of the era. Nothing is different aside from final gear sizes other than (and including) 3.27 were available on the other cars. There's nothing TTA-specific about TTA rear axles.

The only mechanical TTA-specific parts that weren't available on other 1989 FBodies (or any year FBody for that matter) are basically the engine and transmission. Almost everything else is off the shelf factory FBody stuff. Mechanically, it's basically a 1LE GTA with a 3.8 liter SFI turbo V6 and TH200-4R transmission.

[Scott89TTA]

Originally Posted by Lynn D. Brown

One possible disadvantage is, I'm not aware that anyone offers a cast TA-type rear cover for it. Anybody know if anybody sells one ?

not 7.875"...7.750" 9-Bolt... 7.750" (9 bolt) GM Axle

yes...TA/Performance does make a girdle cover for the Australian B-W 9"...

T/A Perf 9-bolt girdle cover

Rear End Girdles