D30 Axle Ratio I.D.

I found a 84 D30 at the bone yard, but the axle tag was rusted beyond identification. The numbers stamped on the housing:

037071
83 22 followed by an upside down 2

Rear D20 had 891 in big numbers under that was a small tag with the number 201, under that was a 1 then a large O then 3235891.

I tried dividing stamped numbers on the housing for gear ratio like you can with an 2a axle, but the numbers aren’t right.

Thanks in advance for your help.

 

I've never heard of ratios being stamped into the housing. SOP, if the tag is gone, you remove the cover and look at the numbers stamped into the ring gear.

The rear is a Corporate 20? I expect it has markings too, maybe on the ring gear... don't know.

 

Chuck
on the AMC 20
try looking at the machined/flat surface to the right side (passenger) of the diff cover; next to the hole where a case spreader might be used; you are looking for a single letter or 2 letters
for 8-17-1981 and later, decode as follows:
2:73 D = less locking diff DD = with locking diff
3:31 B = " " " BB = " " "
3:54 A = " " " AA = " " "
4:10 C = " " " CC = " " "

as always, this means nothing if a PO has changed ratios in the axles
best to yank the cover unless you know the history

 

Or rotate the wheel and count the rotations of the driveshaft. (If it is an open diff, keep one wheel stationary and rotate the other one 2 times)

 

Thanks guys it’s all great info. I will take a look before work tomorrow morning, hopefully it’s “AA”.

 

I had a chance to look at the AMC 20 and the only letter I could find was a large N. I then removed the cover from the D30 and found these numbers on the ring gear,

6 983 DANA D 32857 A30348 46-13 665.

The only number I found on the pinion gear was 665. I’m guessing with the lone “D” it’s 2:73 ratio.

 

46/13 = 3.54

 

GREAT! It's the ratio I wanted, thanks Tim.