Hey all, I was looking everywhere to find out what gears I have on my 88 GTA without any luck. A VIN decoder does not realy help either.....

The question is, how do I find out if I have 2.77 or 3.27 gears? These were the two options offered on the 88 GTA model including an optional Borg Warner rear end. I bought the car last year and trying to restore it a bit without any paperwork provided from the previous owner.

Any help would be appreciated.

Thanks!

 

Look for the stamped #'s on the Pumkin, sometimes on the axel tube also. If the gears are factory and never changed, you can call your local Chevy house - service department and give them the last 8 digits of your VIN, they can look it up off that. Worst case, drop the pan cover, there will be some #'s on the Ring gear, ie (41.11 = 3.73).

 

have you tried getting under the car and looking on the gear it's self? it's usually a very good way to figure it out.

 

Thx guys, the housing is realy dirty so I probably missed the number when looking, will degrease the **** and try again.

 

finding to code won't tell you what it has, only what it had when it left the assembly line.

 

In addition to what ede eluded to there is no way to tell what gear is in your car now without pulling the cover. Referencing RPO's and external casting numbers only tell you what the factory installed in the rear. They don't tell you what Joe Smith swapped into it in his backyard in '92.

 

Cmon, piece of chalk and a jack.

Posi is easy, if posi is shot or it a sinngle legger, double your driveshaft count.

I agree it'd probably be good to pull the cover and refresh the fluid, but definitely not necessary to cure an inquiring mind.

Posi..Both tires off the ground. One complete rev of the tires and count the # of times the drive shaft spins, or vice versa and spin the drive shaft until the tires make one full rev.

You'll be so close, no room for errors.

Chalk is to mark reference points on the tire/ground or driveshaft/housing.

If single legger or posi completly shot, the multiply the driveshaft revs X2...



Sure, there's instances where someone added some locker, etc that may skew it (dunno, never had one) but I'd bet that in 99% of those cases, that information is passed down as the car is sold...

I/e "The uy I bought it from said the guy he bought it from, said it had ...installed"

Anyway, I hate old rear gearlube...

 

There should be a tag on one of the cover bolts that gives the ratio.

 

Since yours is an 87, it will be more likely a 3.27, like mine. What does it idle at in OD going 35?

 

Actualy its an 88, My profile has an error in it. I am prety much sure the rear is all stock as the car never had any modifications done to it besides the idiot before me installing a crappy set of plug wires.

I'm going to pull the rear cover off and top it off with clean fluid, probably the best idea.

Thanks for the help though on helping me to find out if there is a posi. I have not driven the car in a while so I cannot realy tell you what it runs at in od @ 35mph. I'm in the military so the car is at my mom's house, trying to get it back to my residence so I can work on it.

 

The tag you're looking for will be on the front of the right axle tube about three inches from the differential carrier. The first three letters will be axle ratio that the rear end came from the factory with. If the original owner was the idiot you say he was, then it's a pretty safe bet that the original gears are still in there. You'll need some wire brushes and cleaner to get all the grime, dirt and rust of though.

 

Call the dealership, give them the last 8 digitsof the VIN# and you'll have your answer. That is if for sure you know someone hasn't changed them already.