amc 20 axle question

[rigrunner567]

when i bought my 78 CJ7 the rear would pop if you tried to spin on dry pavement or hard packed dirt. today after some very light wheeling the rear sounds like a train around 40 miles and hour. almost like the chuga chuga of a train. when i got home it will only spin the right tire and absolutly nothing happens with the left. i jacked the jeep up and i can spin the wheels by hand and if i turn just the right side the left soesnt move unless i spin the wheel backwards. is this an idication of a stripped spline on one or the other axle shafts?

 

[mylittlecj5]

Do you know if you have a Limited slip diff. or locker inside?
The only real way to tell whats wrong is to open it up and look...You need to change the diff. fluid anyways, right?

 

[rigrunner567]

had it changed a little over a month ago. what am i looking for inside the diff? im new to rears.

 

[Sasquach]

had it changed a little over a month ago. what am i looking for inside the diff? im new to rears.

Another good reason to do it yourself, you can see the oil that came out and if it's full of metal particles/gear bits/what have you. Pull the cover and drain into a clean pan so you can know what came out, then look over the gears for anything abnormal.

 

[rigrunner567]

ok. thanks. im pretty sure it has the 2 peice axles. if i dont see anything in the diff housing whats next?

 

[Old Dog]

sounds like you spun a hub. Time for 1 piece axles.

 

[rigrunner567]

is there a way to determain if a hub is stripped. im going to try and take a look this weekend. i recently got laid off and am dreading a high dollar fix smh

 

[rigrunner567]

if its just a hub can i still drive it?

 

[Sasquach]

IF it is the hub to axle spline you could drive it as long as it will still go, but is it wise? NO.
IF it's not the hub and it's within the differential you will only continue to make maters worse.
Pull the cover.

 

[BusaDave9]

i jacked the jeep up and i can spin the wheels by hand and if i turn just the right side the left soesnt move unless i spin the wheel backwards. is this an idication of a stripped spline on one or the other axle shafts?

Was the TCase or tranny in neautral when you did this?
If you stripped the splines of the OEM 2 piece axles I can't imagine the hub would rotate that easily. To check out if that's the problem take off the wheel. You can look at the axle shaft and see if it rotates a different speed from the hub. The axle shaft is in the center of this nut.

 

[Sasquach]

Or just pop off the hub cap.

 

[rigrunner567]

t case was in 2 hi when it made the popping npise. when it popped it sounded like a gear stripped. just took it and pressure washed the jeep so i can get to everything. it sounds to me like the noise is coming from the drivers side wheel. its not as loud since i pressure washed it. maybe something is in the drum? how do i get the dust cover off the center of the drum to see the axle shaft? mine will not move. hammer and chisle? i am guessing its rusted on there.

 

[BusaDave9]

i jacked the jeep up and i can spin the wheels by hand and if i turn just the right side the left soesnt move unless i spin the wheel backwards. is this an idication of a stripped spline on one or the other axle shafts?

But was the TCase or Tranny in neutral when you jacked up the rear end and rotated the tires?
I'm wondering if the driveshaft was rotating

 

[rigrunner567]

i tried turning them in both nuetral and with Transmission in gear/ drive shaft is turning

 

[BusaDave9]

With everything in gear you should not be able to turn the drive shaft unless you are also turning the engine. Jack up only one tire. Put the tranny in 1st and try turning the wheel.
If you can turn the wheel then take off the dust cover over the axle nut.


This is not your axle but it's similar.
If you damage the dust cover don't worry. It's only purpose is to prevent the axle nut from getting dusty and dirty. God only knows why that would be a problem. If you have to remove the axle replace it with a one piece axle.

 

[rigrunner567]

ok. will give it a try now. thanks for the pics. very helpfull

 

[rigrunner567]

with one tire off ground and Transmission in gear the tires will not rotate. the left wheel has some play in it like a front wheel bearing on a 2wd car if the are loose. trying to get the dust cover off now.

 

[BusaDave9]

with one tire off ground and trans in gear the tires will not rotate. the left wheel has some play in it like a front wheel bearing on a 2wd car if the are loose. trying to get the dust cover off now.

It no longer sounds like it's the axle shaft. It could be a bad bearing if it came from one side. Sometimes it's hard to tell where the noise is if you are in the drivers seat. Have someone outside the jeep listen.
It may be the differential. A locker does make noises as it locks and unlocks. Do you know if you have a locker or Limited slip?
How does it drive on the street?

 

[BusaDave9]

I take that back: it very well could be you spun the hub on the shaft.
Or bad axle bearing
Or diff

 

[BusaDave9]

after re-reading your post I think the most likely cause that noise is the axle shaft spinning in the hub. You may not see much when you look at the axle nut but look for metal shavings and evidence that the shaft spun.
If it only makes this noise when under heavy power you might be able to drive it a little if you are careful with the gas until your 1 piece axle shows up.