Hello,

My 03 1500 with the 9.25 LSD rear end seems to finally be on its way out, it's gone 291,00 miles so I figured I can't complain. When I'm driving I got this low rhythmic "wha wha wha" sound that speeds up as I go faster, both when coasting and accelerating. The last time I changed the fluid very recently it looked good without any glitter and the gears looked fine, I wonder if I can just replace the bearings and re-use the gears and shims? Or will I have to set the depth again? This is my first rear end job and I'm willing to tackle this. I know it's not the rear wheel bearings or u-joints because I've already replaced them. The LSD clutches are worn out and need to be replaced anyway haha. Or would I be better off ordering a whole new carrier and doing the whole thing new? Thanks for any details.

 

Think I would rotate the tires first, and see if the noise changed at all.

If you are changing bearings and such, then yes, you need to remeasure pinion depth, backlash, and all the other fun stuff.

 

Ill probably go ahead and get their balance checked while I'm at it just to rule it out, but they're pretty new tires and so far have worn good. But I guess that doesn't mean anything anymore nowadays.

In that case when I get to it I'll just order all the tools and do the whole thing. Thanks for your answer.

 

Check with your local auto parts store. The big chain fellers may be able to 'rent' you the tools. Unless you plan on doing rear-end rebuilds regularly, the tools are a significant investment.

 

Appreciate you, also debating just buying a reman diff assembly with my tax return and calling it a day lol.

 

Not an inexpensive route either..... If the gears and such in yours are still in good shape, doing a rebuild will save ya a few bucks.

 

I’ve had problems with my diff, on my 02, since new! 3.91 ratio LS. Dealership replaced it at 19 K. And replaced the bearings twice before warranty expired. I’ve replaced them again and lived with it, until 2 years ago.
I found East Coast Gear in Lewisburg, North Carolina. They are advertised in All 4 wheel and off road sites. They are an Industrial size company, who does nothing but diffs. The Stock everything from seals to complete Rock Crawler assemblies. They also rebuilt your unit ! Which I had them do.
They used Richmond gears and rebuilt the clutch unit and all new seals and bearings! $1700 , 2 years ago.
I honestly gained 1.5 miles to the gallon/ same ratio 👍 They said and guaranteed it only to use Lucas 85/140 Non synthetic lube and Mopar LS additive.

 

So I decided to go ahead and start tearing into it to see what was going on. The gears look perfect and there's no notable wear besides some metal flakes on the magnet, which is to be expected. All of the carrier bearings and pinion bearings look pretty much fantastic, I'm going to replace them anyway since I'm already in here, got some new timkens. I've recently replaced the rear wheel bearings but as an amateur I didn't check the axle surface the bearing rides on (I did the job in the dark to be honest..) And I've noticed that the surface the passenger axle shaft rides on is extremely pitted and rough...


Driver Side Axle Shaft, looks okay, nothing catches on fingernail

Passenger Side Axle Shaft. Heavily pitted and rough.
Is it possible this could be the sound of my "Wha wha wha wha" and my rapid "thunk thunk thunk" sound? I'm figuring the only real fix to this is to buy new axles. The wheel bearings themselves are new, and inspecting them they still look good, weirdly the old ones looked perfect when I took them out too, despite the axle looking like this.

I also noticed that when the rear of my truck was jacked up in the air and running in drive, the rear wheels had a noticeable wobble to them, like the axles were bent, but they look straight, and checking them with my ruler as best as I can dont appear to be bent. Is it normal for the rear wheels to have some slight wobble to them when jacked up in the air and running in drive? I know in and out play is normal due to the c-clips in the carrier. The tires are wearing normally, and are relatively new and have been balanced not long ago.

This job has been relatively fun to attempt haha

Edit: I have also rotated the tires recently, made no change in anything.

 

I'd be replacing that axle, at the very least.....

Do the bearing rollers ride directly ON the axle? Or is there an inner race that axle slips thru?

 

They do, there's no inner sleeve, which is interesting. I went ahead and ordered two new Dana axles off rock auto. Which won't be here until the 4th unfortunately. I used a screwdriver under the truck while it was running on stands to try to pinpoint the noise but it was pretty inconclusive, everything sounded grindy. But it was super loud on that side with the bad axle surface, and now I know why.