Which Rearend do I have??

[Lortay5408]

Hi all,

Been doing some work on the GTA, and I need some help with some data about the rear-end on my car.

I've searched across the internet for info on what gears I have. Car is a 1988 GTA.

From that, I gather that I have a 9-bolt B-W Posi. Now, that narrows it down to 2.77, 3.27, or 3.45(please God this one) gears.

I found the RPO code GW6, which using this website, means I have a 3.27 gear. But, at 70mph the tach reads approx. 2600 rpms. Seems like that would be 3.45 gears. Let me know what I missed and thanks in advance!

EDIT: Car is 305TPI and A4.

[hoogiesngrinderz]

None correlate. 2.77 rear in third gear is about 70, 4th gear with 4.11 rear would be around 70.

3.45 rears only came with the 305 manual cars.

[Nocooler]

99% chance it's 3.27's - is the converter locking properly?

[Lortay5408]

Everything is working as it should. I was leaning towards the 3.27 but I couldn't confirm 100% the 3.45s came with manuals only. Some places I read said my car was a manual...... . I was thrown off by the rpms at highway speed, they were higher than I thought they'd be. I'll know more tomorrow when I have the car in the air and can read the codes. Thanks guys!

[Lortay5408]

I think there is a 4.11 gear in it. Highway is approx. 2750. Good passing power though.

[landstuhltaylor]

I think there is a 4.11 gear in it. Highway is approx. 2750. Good passing power though.

At first I thought that wasn't too bad, then I realized I haven't really driven my car in years. Been in the M3 that's 3000+ on the highway, Miata that's 4000, and the bike that's 7000.

[Lortay5408]

Yeah my passat 5speed runs 3000, too. I was hoping the firebird would be a nice cruiser