what rear end ratio?

[averagewhiteboy]

Hey guys.

I was just thinking about it today and couldn't find the information anywhere. What rear end ration do I have? I have an 85 Grand Prix with the 3.8 V6 and 3 speed auto. I don't know if it'd be some crappy rear end, or if they'd try to put something a little higher to get a tiny bit of performance from that crappy 231. And is whatever I have a reasonable ratio for a V8? I know the Monte SS's had 2 different ratios. A lower one earlier on, and a higher one in later production. I'm just too lazy right now to look at exactly what they are. lol. Please help, yo!

:lol:

 

[85 Cutlass Brougham]

Hey guys.

I was just thinking about it today and couldn't find the information anywhere. What rear end ration do I have? I have an 85 Grand Prix with the 3.8 V6 and 3 speed auto. I don't know if it'd be some crappy rear end, or if they'd try to put something a little higher to get a tiny bit of performance from that crappy 231. And is whatever I have a reasonable ratio for a V8? I know the Monte SS's had 2 different ratios. A lower one earlier on, and a higher one in later production. I'm just too lazy right now to look at exactly what they are. lol. Please help, yo!

:lol:

If you have the original decklid, you can find out on the data sticker. It likely is the putrid 2.41 axle ( code GU1 , IIRC) but could be the 3.23 optional ratio ( code GU5?) which could be ordered only with the 231/TH200C drivetrain. I just pulled one from a V6 4 door Regal a few weeks ago for my Cutlass, so they are out there.

 

[pontiacgp]

here's a link to differential codes and some information...

http://www.g-body.org/tnt/diffs/diff-codes.php

 

[beermonkey9417]

i read in a book to get a rough estamit of yer rear gear is to jack up the back of the car and put it in to "N" . then mark with chalk on the tire and then on the u joint or drive shaft and one on the housing making the lines line up. then turn the tire once and count how many times the line on the driveshaft passes and thatll tell ya the ratio. hope this helps

 

[Pigsdaddy]

You can always just pop off the inspection plate and read the numbers that are stamped on the ring gear. Divide the lower number into the higher number to get the ratio. Example 41:17 = 2.41.

 

[Pigsdaddy]

Hey, P.S.--- If you decide to pull the inspection plate off to check the ratio, you better make sure that the fill plug can be easily removed before draining the gear oil. I had one that had to be drilled out after it broke a #7 easy out. Most are pretty good to turn loose.