AMC Model 20 differential problem

[tom_b]

I have a 1984 jeep cj7 and it has that diff and it just crapped out the other day and I can't figure out what is wrong. It just stopped putting power to the rear wheels. The driveshaft turns the pinion and ring gear and the wheels turn the differential side gears, but the two do not meet. The differential case spins with the ring gear when the drive shaft is turned and the differential side gears turn when the wheels are turned. Can't understand what is wrong and if it is a big problem or a relatively easy fix. Any help would be greatly appreciated. Tom

 

[wm69]

Sounds like you spun a hub on an axle. It's really common with the stock AMC20 rear axles. You have an splined axle shaft and the hub slips up on the splines. Weak design and a lot of times the splines will give and you get an axle that spins in the hub. If you jacked the jeep up off the ground it takes all the work out of spinning the wheel so there might be enough of the splines left to still turn the shaft (it just won't do it with any weight on it). Get one piece axles and you won't have the problem again. Moser and Superior make good ones, and I've heard Yukon are good too. I've had superiors for almost 10 years now with no problems. Don't get cheap one piece axle kits; stick with one of the 3 I listed. There's a lot of junk "upgrades" for sale out there and you get what you pay for.

 

[gunner]

I put a Superior one piece in my CJ a few years back. It was well worth the 300 bucks, and it wasn't too difficult to install. Just remember to have the bering retainer rings pressed on at a shop if you don't have the press at home. I ruined two sets of berings and rings trying to be cheap s.o.b. with some home made b.s. press I came up with. It only cost 20 bucks to have them pressed on at a shop - I wasted that much in money and time screwing around and getting new berrings.

In any case, the Superior was worth the price.

 

[firemanharry]

I'm running Superior's also with no problems for 2 years.

 

[dju91001]

I just installed the alloy one piece axles in my cj7, and im running 33" tires . I havent had any problems yet. My buddy is running superiors in his and he is having hell with the seals leaking. He has replaced them 2 or 3 times in the last year now.

 

[firemanharry]

My buddy is running superiors in his and he is having hell with the seals leaking. He has replaced them 2 or 3 times in the last year now.

Could be that your buddy has bent axle tubes. Common problem with 20s are the weak tubes. I trussed my tubes and welded them to the center.