I had my pinion seal replaced about 6 months ago by a transmission shop. It started leaking again a few months ago but not enough to drip on the ground so after reading about the issue on here I decided to let it go. The other day, I took a 60 mile trip (pretty far for my regular driving) and the next day all of a sudden I am getting a constant whirring noise between 5 and 40 mph.

Could I have pumped enough fluid out of the diff during my trip to cause the fluid to be low enough to make this sound or could an incorrect preload setting when the shop put a new pinion seal in have caused my pinion bearing to fail? The noise is there no matter if the differential is loaded up or not. If it is the pinion bearing how would I test to make sure?

Thank you for the input.

 

My guess would be incorrect bearing preload. But if your seal is leaking again and the noise wasn't there immediately after the shop replaced the seal I would bet that the pinion nut backed off some. It happens a lot on these cars. I would check to see if you have any movement in the pinion

 

if you lost that much fluid out the pinion seal, you would have smelled it when you got out of the car, and most likely while driving as gear oil will have splashed and coated everything in the area.

when a pinion seal leaks, it's because either (a) the seal is bad, (b) the yoke the seal rides on is bad, or (c) both. More often than not to properly fix a leaking pinion seal you need to replace the yoke which the seal rides on. if there's a groove worn in the yoke from the old seal, the new seal will leak. if there's a burr or runout on the old yoke, it will cause the new seal to leak.

as for the whirring noise, it will either be the pinion bearing or gear pattern between the pinion and ring gear. i forget which way it works but... upon decel i think the pinion gear gets pulled inward by the ring gear and on if you get noise only on decel but not on accel then it's most likely just the pinion bearing or pinion bearing preload. if you get the noise on acceleration, then the ring gear is forcing the pinion away and into the pinion bearing and is less noisy so if no noise on accel but on decel then it's more likely to be pinion bearing. but if noise on accel then you're looking at a gear pattern problem and a new gear set.

 

Thank you guys for the great information.

I did a little road testing and determined acceleration/deceleration makes no difference on sound. The only thing that changes it is road speed whuch changes how loud it is. It also struck me that I am not sure if the noise is coming from the center or the driver's side. I was unable to determine while driving so today I'll find a willing soul to ride in the back to help me try to pinpoint it. Does this sound like it could be an axle bearing?

 

Alright, so the noise is definitely coming from the general area of the differential. I checked the fluid level and its right where it needs to be at the level of the fill plug and the fluid looks fairly clean. I checked for loosness in the pinion/flange and its nice and tight. There is some rotational play in the right (passenger) rear wheel that allows it to rotate a little before turning the left rear wheel. Is this the backlash in the gearing? However, on the left rear wheel there is no play before the right wheel is engaged. Which should it be? Is this normal for this differential? If any clarification is needed I have a video I can put up.

Thank you for your input.

 

If you want info,we can't guess if we don't know info of your vehicle. year would be helpful !!!

 

Its a 2000, has the 3.42 limited slip.

 

Up to and including 1998,the rears had Auburn 'posi' carriers,which had very little 'looseness',and that only came from the spider gears. 1999 and later have the Torsen 'posi' which has a gear train setup in the carrier instead of a clutch setup. The gear train setup has a lot of peculiar looseness variables.

Torsen


Auburn

 

Alright that is good to know. Someone was very creative in coming up with the design for the torsen.

So I guess the next thing to look at is carrier bearings. Is there any way to test these without opening the entire differential up?

 

Now to the 'whirring noise'. If the noise seems 'in time' with tire rotation,it's wheel bearing or carrier bearing. If it's more frequent than tire rotation(3 times as frequent),it pinion bearing.

 

Bringing this back, took it to a gear shop and turns out it was a bad pinion bearing. Too high of a preload last time it was put back together, not happy with the shop that swapped the pinion seal. But the guys at the gear shop were great, knew right away after hearing it what was wrong and showed me the bad bearing, ended up replacing pinion and carrier bearings as well as all the seals, car has never been quieter on the expressway. Thanks for all the info guys.

 

Was in the same boat had a buddy that knew how to redo the rear end ratech bearings and the pinion spacer made me a happy man. But ive been told so many times 12 bolt so this winter Im going with a strange rear end and 4.10s