Question About the GTO's A$$ end

**SSG Duncan** · 11-03-2010, 12:16 AM

I would like to install a taller set of gears and don't know what to shop for. EX... 12" rear end, 6 bolt? I have no idea. Also I hear a clunking sound from the rear. Nothing is loose. I had the same sound when I had my 00 B4C. Thanks for any help you can give me.

First Tank!!!

**TLS_Addict** · 11-03-2010, 07:50 AM

That clunking could be from the ring and pinion have a large gap. My GTO did that if I would go from reverse to forward. It had a lot of play in it, most are known for it after a while.

I think that the Lumina SS (same as GTO in middle east) came wit 3.07or something but not sure.

**Texas Jack** · 11-03-2010, 09:49 AM

Stock gears in all Gtos are 3:46. Use the search or the net and you will find a lot of info. Good luck

**JAX04** · 11-03-2010, 10:04 AM

GFORCE engineering will be a good place for you look up. and the stock diff is kind of known for issues.

**cammed goat** · 11-03-2010, 02:49 PM

I would STILL love to find out how some of these GTOs in GMHTP with larger cubes or forced induction STILL run on the stock rear. IMPOSSIBLE!!!

**derbs** · 11-03-2010, 04:36 PM

Originally Posted by JAX04

GFORCE engineering will be a good place for you look up. and the stock diff is kind of known for issues.

You forgot the 1320 in the name.

**Texas Jack** · 11-03-2010, 04:42 PM

Exotic Performace Plus has a moser M9 straight axle that will bolt in for 4k, Take a look, it is very cool!

**TLS_Addict** · 11-03-2010, 06:42 PM

Originally Posted by cammed goat

I would STILL love to find out how some of these GTOs in GMHTP with larger cubes or forced induction STILL run on the stock rear. IMPOSSIBLE!!!

No doubt! I saw some guys with FI running more highway gears but on the stock rear.

**cammed goat** · 11-04-2010, 04:25 PM

Originally Posted by TLS_Addict

No doubt! I saw some guys with FI running more highway gears but on the stock rear.

Yah. When I read the specs in the magazine, where it reads "REAREND" it would read "STOCK 3:46".

**Texas Jack** · 11-04-2010, 06:39 PM

Look at the GTO ET list and qwkgto ran a twin turbo set up 9.52 @ 144 1.55 60 ft on a stock rear!

**mark21742** · 11-05-2010, 10:57 AM

408 stroker with built tranny and 3,800 stall here...89,542 miles, still running my stock rear

**SSG Duncan** · 11-07-2010, 12:26 AM

Originally Posted by JAX04

GFORCE engineering will be a good place for you look up. and the stock diff is kind of known for issues.

Just what I was looking for thanks for all the help. Soo I wonder if a new ring and pinion would stop the clunk in the rear?

**cammed goat** · 11-07-2010, 08:16 AM

Check your U-joints in the driveshaft as well.

**SSG Duncan** · 11-07-2010, 03:05 PM

Originally Posted by cammed goat

Check your U-joints in the driveshaft as well.

Hmm I would think to check that I would put the rear in the air. Car in gear with hand break on and check for slack in Drive shaft. Does that sound right.

**Johnstonj2005** · 11-07-2010, 05:39 PM

I replaced my stock 3.46's with 3.91's after I ate half the teeth off the non shot peened 04 pinion gear. Bow my 3.91's are clunking while under light to moderate load. Heavy load or clutch pushed in the clunking goes away. Yay for "stock" rear ends