Rear Differential Work and 3rd Member Rebuild (1 Viewer)

[78fj40mg]

Hey guys!
I have a strange sound coming from the left rear axle bearing or possibly the diff? Upon rotation of the wheel hub I noticed a bumpy and somewhat loud cranking sound, it sounds like a bad bearing or possibly a bad diff. not sure what it should sound like. The axle also appears to have excessive horizontal play, maybe. Not sure how much lateral travel the axle should have. I need help diagnosing this problem.
Thanks in advance!
Mike

Here's a vid of all the axle/hub/diff sounds.

 

[Stumpalama]

Can you hear it at the diff as well? Is your diff full? There is usually some noise from the axle turning, but not quite that loud, that I recall. Get an automotive stethoscope or stick a piece of metal to the diff and hold your ear near it while turning the axle and see if you can hear the noise at the diff. That lateral play seems a little excessive as well. The FSM shows you should have between .060-.465mm of thrust clearance between the end of the axle shaft and the pinion shaft (also known as the pillow block shaft inside the differential) which should translate to approximately the same amount of lateral movement at the end of the axle.

 

[reddingcruiser]

I agree the lateral play seems excessive. I would pull the rear cover and look inside. Once you pull the drain plug you might get a clue to your problem if there is a pile of shavings on it. No matter the problem you will going through the rear cover to get to it.

 

[78fj40mg]

Hey Stump - Yeah the diff was full of oil, in fact it had too much oil in it. The diff was pretty loud as well, so drained the oil and popped the cover to see what's the story, all the gears appear to be intact. When turning the wheels I get some clicking sounds from the diff and pinion and clicking from the left bearing. I'll post some pics of the diff and maybe another vid while it's turning.

 

[reddingcruiser]

Did you check the pinion? Can you move it in/out or side to side?

 

[78fj40mg]

I agree the lateral play seems excessive. I would pull the rear cover and look inside. Once you pull the drain plug you might get a clue to your problem if there is a pile of shavings on it. No matter the problem you will going through the rear cover to get to it.

Hey Dick, once I pulled the diff oil plug noticed a nice fine pile of shavings. The oil seemed pretty old and stinky. I'll go take some pics.

 

[78fj40mg]

Did you check the pinion? Can you move it in/out or side to side?

No I did not. Do I need to remove the drive shaft first?

 

[reddingcruiser]

It helps but not necessary. The only slack you should feel is the backlash (rotational). Any in/out or side to side movement indicates worn pinion bearing or loose pinion nut, which could be caused by a failing bearing. Was there any play at the end of the axle other than the lateral movement??

 

[78fj40mg]

Here's another vid

 

[78fj40mg]

Here's another one

 

[reddingcruiser]

Well, without being right there it looks like you may have two issues. Too much backlash on the ring and pinion. And too much end play on the axles, which is letting the side gears also move in and out. I think that's what is making the rattling noise. Just my long distance opinion.

 

[reddingcruiser]

Backlash should be around 0.008. Do you have a dial indicator and mag base?

 

[78fj40mg]

I was not able to move nor hear any sounds from the pinion gear

Pinion gear

Center pillow and two axle shafts

Left rear brake assembly

 

[78fj40mg]

Backlash should be around 0.008. Do you have a dial indicator and mag base?

I sure don't, is it possible to check the backlash with a feeler gauge?

 

[78fj40mg]

It helps but not necessary. The only slack you should feel is the backlash (rotational). Any in/out or side to side movement indicates worn pinion bearing or loose pinion nut, which could be caused by a failing bearing. Was there any play at the end of the axle other than the lateral movement??

No other axle play just the lateral.

 

[reddingcruiser]

No. You need a dial indicator.
Do the side gear teeth on the ring gear side have a "curve" along the top of the teeth???? Or is that an optical illusion?

 

[78fj40mg]

Tomorrow I'll remove the drive shaft and check pinion for play and also remove the pinion cover to check the bearing etc.

 

[reddingcruiser]

Check the backlash to see what you have. Should not exceed 0.009.
If there's no other play in the pinion and the bearing feels fine otherwise and the pinion seal is not leaking, I wouldn't break the nut loose to pull the companion flange off. A clear close-up of the side gears would be nice.

 

[78fj40mg]

No. You need a dial indicator.
Do the side gear teeth on the ring gear side have a "curve" along the top of the teeth???? Or is that an optical illusion?

Unfortunately it's not an optical illusion, they are rounded, here's a better pic.

I guess that's not good. Does the ring gear need replacing?

 

[reddingcruiser]

No, the ring gear looks fine. I'm asking about the differential side gears ( Where the axles come through). The top edge of those teeth should be straight and not worn to a "knife" edge.