Check rear end gears
 

I posted awhile back about how to find out what kind of gears you have and never got a striaght answer. I thought I read that you can turn the drive shaft and count how many times the wheels turn but does anyone know for sure? I know my speedo is off by atleast 10mph and sometimes 15mph at higher speeds but before I start ripping **** apart I want to see if the stock 3.27s are in the car.

RE: Check rear end gears
 

Its for my 96 GT. My brother was going to buy it but he found a 96 GT with less miles for less so hes jumping on that one. I dont blame him because its a very clean car and the original owner is the seller.

RE: Check rear end gears
 

There should be a tag on your rear end. What does it say?

RE: Check rear end gears
 

Yes I know it says 3L27 which means 3.27's with limited slip. Now does anyone know how to check to see which gears you have.

RE: Check rear end gears
 

You gotta count teeth on ring and pinion.

RE: Check rear end gears
 

Well theres that but I heard there was some way to tell without tearing the rear end open. Anyone have a clue of how to do this? I thought I saw it on here somewhere???

RE: Check rear end gears
 

Bingo! I found it.

What gear ratio do I have?
Jack up one tire if you have an open diff, or both tires if you have a working posi or locking differential. Rotate the tire one full revolution for posis and lockers and 2 full revolutions for open diffs. Carefully count the number of full revolutions the driveshaft makes. This is your gear ratio. In other words, if the drive shaft turns 3 ¾ turns, you probably have a 3.73 gear ratio. Turning the tire for twice the number of full revolutions and dividing the drive shaft revolutions by two will give you a more accurate reading.

I'll check mine tomorrow and see if that works.

RE: Check rear end gears
 

it will get you really close if you have the stock sized rubber on there but remember that it won't be exact. It's hard to tell the difference between the 3.27s and 3.55s doing it that way. Put a chalk mark or something on your drive shaft.

You said that your speedo is reading 10 - 15 mph off. I assume you are saying that it reads faster than you are actually going, right?

My 4.10s put the speedo off by about 25 MPH or so.


There is also another way to do it if you have a tuner. You can tell the tuner to calibrate the speedo fo 3.73:1 - get your buddy to drive beside you and give you a hand signal every 10 MPH and see if it's right. Then try it for 3.55s and so on.

RE: Check rear end gears
 

Yes the speedo is faster. Thanks for the chalk idea I will def. do that. I have the right size tires on there. 245/45/17's. Im gonna go check now. I think it has 3.73's but im not sure. I'll post back in about an hour, I got some other stuff I gotta do also.

RE: Check rear end gears
 

If it comes to that I will but I like to try the free stuff first.:D