What's the diff...

[WillC]

http://nationwideparts.com/differentials.htm

[Mr Rock]

This is better that the one I have hanging in my garage!

Now do you have a link that will decifer the gear ratio tag???

[WillC]

 Jack up the rear axle and support it with jack stands. Put the transmission in neutral and then rotate the rear drive shaft by hand. While turning, count the number of drive shaft revolutions required for one revolution of the tire. If the drive shaft turns approximately 3-3/4 times, you have a 3.73 ratio, etc. It may help to use a piece of chalk mark a reference point on both the tire and drive shaft. For increased accuracy it is recommended to rotate the wheels two times and divide the result by two. You may have different gearing front to rear (but the difference is typically very slight) so be sure to check the other axle too.

Number of Turns       Approximate Gear Ratio
2 - 3/4                     2.72:1 or 2.77:1
3 - 0                              3.07:1
3 - 1/2                           3.54:1
3 - 3/4                           3.73:1
4 - 0                              4.10:1
4 - 1/2                           4.56:1
4 - 3/4                           4.88:1

[gearhead1985B]

the most accurate way is to pop the cover and look at the ring gear it tells you what it is

[Flex]

the laziest way is to call the dealership with ur vin.

[gearhead1985B]

the laziest way is to call the dealership with ur vin.

that does not always work i grabed a 8.8 off the vin and was told 4.10 ls from the junk yard and called the dealer and got stuck with 3.08 open i still got a hundred for it and broke even

[Mr Rock]

Jack up the rear axle and support it with jack stands. Put the transmission in neutral and then rotate the rear drive shaft by hand. While turning, count the number of drive shaft revolutions required for one revolution of the tire. If the drive shaft turns approximately 3-3/4 times, you have a 3.73 ratio, etc. It may help to use a piece of chalk mark a reference point on both the tire and drive shaft. For increased accuracy it is recommended to rotate the wheels two times and divide the result by two. You may have different gearing front to rear (but the difference is typically very slight) so be sure to check the other axle too.

Number of Turns       Approximate Gear Ratio
2 - 3/4                     2.72:1 or 2.77:1
3 - 0                              3.07:1
3 - 1/2                           3.54:1
3 - 3/4                           3.73:1
4 - 0                              4.10:1
4 - 1/2                           4.56:1
4 - 3/4                           4.88:1

I did this and only got about 1 3/4 turns (1.70:1 ?which I hever heard of), then I heard that for an open carrier you have to make the wheel go around twice without dividing to get the correct ratio. This seems to hold true as that puts it closer to 3.40 and on one of the FSJ web sites they list the 84-86 grand waggy's as having a 3.31.

The tag on the diff reads;
5365153
3  31  43  13

So I'm thinking the first two numbers on the bottom row are the gear ratio.

[gearhead1985B]

Jack up the rear axle and support it with jack stands. Put the transmission in neutral and then rotate the rear drive shaft by hand. While turning, count the number of drive shaft revolutions required for one revolution of the tire. If the drive shaft turns approximately 3-3/4 times, you have a 3.73 ratio, etc. It may help to use a piece of chalk mark a reference point on both the tire and drive shaft. For increased accuracy it is recommended to rotate the wheels two times and divide the result by two. You may have different gearing front to rear (but the difference is typically very slight) so be sure to check the other axle too.

Number of Turns       Approximate Gear Ratio
2 - 3/4                     2.72:1 or 2.77:1
3 - 0                              3.07:1
3 - 1/2                           3.54:1
3 - 3/4                           3.73:1
4 - 0                              4.10:1
4 - 1/2                           4.56:1
4 - 3/4                           4.88:1

I did this and only got about 1 3/4 turns (1.70:1 ?which I hever heard of), then I heard that for an open carrier you have to make the wheel go around twice without dividing to get the correct ratio. This seems to hold true as that puts it closer to 3.40 and on one of the FSJ web sites they list the 84-86 grand waggy's as having a 3.31.

The tag on the diff reads;
5365153
3  31  43  13

So I'm thinking the first two numbers on the bottom row are the gear ratio.

you are right but pop the cover read the numbers on the ring gear the last two will tell you the tooth count and then devide

3.31 is a verry common ratio for the waggy d44 that is what i have