Stupid rear end ques.#%$#

[dempsy1]

Ok so I know I have a AMC 20 rear---round with 12 bolts I also know it is pretty worn I have been trying to figure out what gears are in it. I cannot read the stamped on code or even see it--- One guy said jack up the rear end and mark tires and diff. and turn ok tires turn but drive shaft does not---told it does not turn b/c of wear on gears???? Can somebody give me a better idea or how can I identify gears on front dana axle??? NO plate. And please keep in mind with your reply that I am no great mechanic so I kinda need it kept simple step by step.


Thanks J

 

[Bounty__Hunter]

Best sure-fire method to determine gear ratio is to pull the diff cover and check the numbers stamped on the side of the ring gear. Look for a pair of numbers, both usually 2 digits. This will be the tooth count of the ring gear and the pinion gear. Divide the large number by the small number. ex. 41 10 would be 4.10 gear ratio.

 

[wrangler76]

^^^ best way. But, once you have it cracked, you can also count the teeth. #ring teeth / #pinion teeth

 

[Weylyn]

also give a good reason to replace the gear oil Might as well do the front too. I always run 90. Book calls for the same

 

[84cjseven]

Try turning the drive shaft instead of the tires I think at least one wheel should turn. lol Put transmission or transfer case in neutral.

 

[carnuck]

The rear is stamped next to the cover (pass side) with a letter code. Front diff has a tag on it telling you the ratio (should be pretty matched)

 

[xjmarc]

You only need to jack up one side, put the t-case in neutral and then the drive shaft will turn.

 

[Blacky]

I know I am not adding or helping here but I was wondering.... is there some place to find out gears/ratios for those of us who are lucky enough to have the gears stamped clearly/plainly.
I was told when I bought my XJ that it had 4.56 gearing. This is confirmed for the rear. It is stamped very clearly with a 4.56 on the ring. No mistaking that!
The front, however, is greek to me.
On the side of the gear it is as follows: "820" hand engraved, followed by "D5 40633 304" and about 2 1/2" behind that is "473". Thats it.

"820 D5 40633 304 473"

Only the "820" is hand engraved (by a shakey hand I may say) and the rest is stamped.
What does it all mean????

(signed)
Confused:lol:

 

[Bounty__Hunter]

Those are the only numbers on the ring gear?

 

[Blacky]

Yup! Thats the only numbers on the ring gear. No tags on the pumpkins probably because the gears had been changed.
Again, this is for the front axle/diff on a 96 XJ with what should be a d30, right?
Do any of these numbers make any sense at all? Not to me......

 

[Bounty__Hunter]

You can count the teeth on the ring and pinion to be sure, divide the ring gear by the pinion gear to get the ratio.

 

[Blacky]

Ah........, math.:???: I can do this. No problem. Was hoping to make sense of the stamped #s but in the end I just want to know the ratio for certain to do future work/repairs.

Thanks!!