Who has had rear diff pinion or carrier bearings go bad?

[eurasiaoverland]

96 2.7 5 speed

I've long been tracing a number of noises on my truck, and I'm beginning to suspect that the noise is coming from the rear diff. The truck has about 200k miles and is on its original diff as far as I know.

I'm hoping someone who has had rear diff noise and sorted the problem by replacing the diff bearings can describe similar or different symptoms.

-For a long time I've had a strange, quite light whine when accelerating, particularly around 40 mph. It sounded almost like a hiss, like a noisy drive belt. With time, this noise seems to have become more of an insistent hum, like a noisy steering pump, but has nothing to do with steering effort.

-I have a general vibration at all speeds, which I can feel through the steering wheel and gas pedal, again not related to steering. It's a vibration as if I were running knobbly mud tyres, but I have part-worn very soft winter tyres on at present.

-Most recently, at highway speeds, so about 60 - 65 mph I get a subtle low, droning rumble.

A few points:

-My UJs are all good, no slop whatsoever, regularly greased, the rear UJ is pretty new and a genuine part.

-The driveshaft looks straight, I see no weights missing.

-Wheels are balanced and aligned. Tyres are in good condition as far as I can tell.

-Rear wheel bearings make no funny noises. If I jack the car up and turn the wheels I get the normal faint growl of the splines in the diff (because the crown wheel is not moving), there is no real slop in the bearings.

-The transmission makes no funny noises, and the noises I describe above are not limited to any one gear.

I had the pre-load reset on the diff when I got the car, about 30,000 miles ago. There is no knock or slap when starting off from stationary. The diff has always had a bit of a howl, especially on overrun but this is not directly related to the other noises. This howl might be getting louder or I might be imagining it. I recently noticed a creeping oil leak which looks to be at least partly coming from the pinion shaft oil seal, which was changed when the pre-load on the diff was reset. The diff is running good quality fully synthetic oil.

I'm really looking for a response only from someone who has replaced their rear diff bearings and can give their opinion on these symptoms from that experience.

Thanks

EO

 

[dogtail]

When my pinion bearing went. I could feel play in it. Put in neutral and try to move around driveshaft where connects to diff. Also to rule out driveshaft out of balance, pull out rear driveshaft and drive in 4wd/front wheel drive. Also an out of balance shaft will give the pinion bearing a beating over time. A good driveline shop can balance the shaft cheap.

 

[eurasiaoverland]

When my pinion bearing went. I could feel play in it. Put in neutral and try to move around driveshaft where connects to diff. Also to rule out driveshaft out of balance, pull out rear driveshaft and drive in 4wd/front wheel drive. Also an out of balance shaft will give the pinion bearing a beating over time. A good driveline shop can balance the shaft cheap.

Thanks. I forgot to add that bit - I have no movement of the diff pinion companion flange. I may try removing the rear driveshaft, but won't have time in the next few weeks. Thanks for the tip.

Were your symptoms similar? And when you said your bearing 'went', do you mean a major failure? I can imagine that if there is movemet in the pinion companion flange, the bearing must be pretty bad. On mine, even without movement, the creeping oil leak suggests there is something awry.

 

[JZiggy]

If it is your rear diff bearings the noise will also be load dependent. When at cruising speed it should be noisy when you push the gas but quieter when not. I experienced these symptoms in a previous 4Runner.

 

[brillo_76]

My 01 pinion was destroyed by previous owner. I just replaced the entire 3rd member and Housing. This mostly happens by running the rear end low on gear grease or no gear grease. The 3rd gen are notorious for the housing rusting through and leak all the gear grease out. Especially in the rust belt areas. :[

Sent from my SM-J337V using Tapatalk

 

[eurasiaoverland]

If it is your rear diff bearings the noise will also be load dependent. When at cruising speed it should be noisy when you push the gas but quieter when not. I experienced these symptoms in a previous 4Runner.

Yes, that's part of what I have - it's noisy all the time but more so when under load, plus the certain speed-dependent driveline vibration.

Thanks

 

[dogtail]

Thanks. I forgot to add that bit - I have no movement of the diff pinion companion flange. I may try removing the rear driveshaft, but won't have time in the next few weeks. Thanks for the tip.

Were your symptoms similar? And when you said your bearing 'went', do you mean a major failure? I can imagine that if there is movemet in the pinion companion flange, the bearing must be pretty bad. On mine, even without movement, the creeping oil leak suggests there is something awry.

Well in my case, I was trying to track down some rear end rumbling and found the pinion bearing slop. I had over 300K miles on the original parts so I replaced the wheel bearings, 3rd bearings, rebuilt the driveshaft (new U-joints, DC joint, and balance). With blow by of lube at the pinion, make sure your breather is not clogged.
For rear end noises, I like to jack up the drive wheel or both wheels and run it in gear, banging thru the gears and bringing up to speed so I can track down the source of the noise by climbing underneath if needed. Good to have another person to be in the drivers seat for this while you're trying to listen and feel. It won't be under load, but most noises would be present, and you can simulate somewhat of a load by stuffing it shifting thru the gears.