I have a '90 Cherokee (new to me) with a stock Dana 35C rear. It has an load moan that comes from the rear axle. I don't have any leakage from the diff, but I am suspect. It's not a tire issue and it starts right around 20mph and goes from there.

I also have an '89 Cherokee that I am parting out. Iwas thinking of a swap of the rear, but was hoping to get some additional diagnostic tips before a start that little project. I may upgrade to a dana 44 while I'm going to the trouble, but the direct swap would be easier in the short term.

Any thoughts or advise to help me out?

 

My buddy's 89 did the same thing and his was in the ring gear. We put Lucas gear oil in it since I was a fan of their products and it made it almost silent. Only other thing to be concerned with is the bearings but the oil couldn't hurt.

 

Thanks - Maybe I am over complicating the situation. I swung by the local repair shop a few weeks ago, and they were giving me some line about charging me a few hours of diag time to figure it out... yeah sure.

Maybe I'll just pop the diff cover and take a look around .....

Can anyone give me some tips on the inspection .. what to look for?

-- KC

 

I had a similar sound coming from my 94 and it turned out to be an axle bearing ($35)I would look for metal shavings in the gear oil...Tj

 

x2 on the bearing
are you shure there is oil in the dif

 

Agree that it points to a bearing(s). Also good point on the oil level! I have had pinion bearings go outl...the diff will howl pretty good! Tough to figure out until you tear into it. Tear the rear drums off and check for excessive play in the axle ends. Once your axle bearings are worn the seals will most likely leak soon since the axle is no longer centered in the seal & housing. Sounds like you have your weekend planned...hope it all works out.

 

I would pull the diff cover off drain the oil and inspect all bearings when the fluid is draining check for metal shavings and chunks of metal if you find any you got a problem it could just be that you havent got enough gear oil in your diff though

 

Many thanks for all the input. Today is inspection day, so I'm hoping for easy fix - although swapping a rear just sounds fun I had to get a puller to attack the brake drums so we will see how it goes.

-- KC

 

UPDATE - I pulled the diff cover and found the gear oil was a very milky brown color and low. I also found a leak around the front of the differential pinion shaft. I haven't checked the seals around the axle hubs as of yet.

Also, the rear-most ujoint is SHOT!

Are there seals on front that I need to replace? I haven't found a post that covers this. Any help?

Thanks!

-- KC

 

The pinion seal can be replaced once the yoke is pulled off the pinion's shaft. When the drive shaft is removed the nut in the center of the yoke needs to come off and then the yoke slides off the pinion splines.

Now IMO the seal might be leaking due to what I posted earlier...the pinion bearings might be shot allowing the shaft to move excessively & causing the seal leakage...also worn pinion bearings (or center section bearings in general) will make the rear howl.

I would check out the ring & pinion closely since a leaking pinion seal might be telling a bigger story.

 

I checked the ring and pinion and there does not seem to be any wear. Also, there were no metal shavings, etc in the gear oil. That said, there appears to be some amount of play at the pinion bearing.

What would you suggest I replace to overhaul? Juat the pinion seal and bearing? Is there more to consider - assuming the ring and pinion are not showing wear?

-- KC

 

While you're having it apart, check the carrier bearings thoroughly. If in doubt replace them too. JMO

 

+1 - You are all the way into it now so if you want it fixed right forge ahead. If you have not done alot of gear work you might want to find someone who can check it out. Now we are talking pressing off the pinion bearing etc.


Tom