Why did my pinion bearing start making noise after I replaced rear shocks, springs, sub-frame bushing and differential mount? I had left rear wheel bearings replaced. Pinion bearing started making noise IMMEDIATELY after these repairs. Changed diff fluid to see if that would help and put in new 90 weight. Fluid change did not help noise.

I looked up parts. Pinion bearing $8.35, Pinion seal $6.85, Pinion shaft nut $3.75 and rear housing gasket $2.34 TOTAL $21.29 unless I am overlooking a part. My car has 257,000 miles.

I can buy a used differential 2.88 or 3.07 locally with 150,000 to 200,000 miles for $200

Could I replace the pinion bearing without removing differential from the car?

Thanks.

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1982 300SD Light Blue
2002 Honda Accord SE
1974 Toro Wheel Horse Tractor
2000 Toyota Tundra Pickup

Perhaps when the noise from the other items was taken away you could hear it better ?
Are you SURE it is the pinion BEARING... as compared to the pinion and gears in the differential ?

It always worries me to see a thread with no reply hours after it hits the forum.

I got out my chassis manual on this.... and studied the crazy translations and pictures carefully.
Knowing that I am frugal may help with my crediblity on this one...

GO and get the differential from where ever you can find it... Well worth $200 because even if you tear this thing apart and think you have fixed it you will be going and buying an intact one to replace it with SOON.

It is my considered opinion based on the number of special tools shown in the manual, and the type of bearing it is ( tapered roller ) ... which always require PRELOAD to last... and the fact that while you can replace the pinion seal you have to take the differential APART to press off and on that tapered roller bearing...

Unless you are a well equipted MB dealer with well trained mechanics you can't even redo that bearing out on a workbench... much less in the car...

Thanks leathermang that's exactly what I needed to know with my level of expertise. I guess I could have mine rebuilt later to have a spare just in case.

I will start looking for a low mileage rear end.

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1982 300SD Light Blue
2002 Honda Accord SE
1974 Toro Wheel Horse Tractor
2000 Toyota Tundra Pickup

If you ever get a chance to look at the FSM on this repair you will feel good about just getting that intact rearend....

Have you tested your driveshaft w/ lateral forces? I.E. grab ahold of it and see how much you can move it? also while your there, maybe check the rear wheels/wheel bearings for looseness... maybe something is loose under there from the work that was done.

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Cheers,
Robert

I still don't buy this whole noise bit. It did not sound like a rear diff noise that I've ever heard, it did not change as you loaded the chassis side to side like a wheel bearing. And I don't buy any bearing going that noisy all the sudden like that. His subframe bushings were not that bad, alignment not that off, diff bushing was bad and had the rear sagging, but still. Wish I'd heard it before hand...

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

Nifty little tool set that all MB, Porsche, and VW dealers must have to set up German diffs. Not quite the same as the old white lead set up days.

FWIW, I bought a complete 2.88 diff from Elite MB wrecking yard yesterday. $150 and it felt like a new one.

__________________
You can get farther with a smile and a gun than you can with just a smile.

1984 300D
1985 300CD
1980 300SD
1993 SL500

i would get a second opinion that it is thepinion bearing.
is the seal leaking? it usually does if the outboard bearing is bad...

Does the growl get louder and softer while you accelerate and decell?

installing the diff mount incorrectly can cause the normal diferential noise to resonate like a guitar...

you can check the pinion bearing for noise with the rerar wheels turning while the car is in gear.
of course they are off the ground..

more diagnosois is needed before going off on a pinion bearing tangent..

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79 240D my current toy
42 years a Diesel addict

240D sold
250SE sold
220D sold
280C sold
280S sold
300D (2) sold
300CD sold
300DT sold
300SD sold
380SL sold