Howdy all,

Now that it's been cooling down a bit I've been driving with the windows down and I've noticed a higher pitched mechanical whining noise that appears to be coming from either the transmission or differential when I'm travelling at 25 - 40 MPH. It might be occurring at higher speeds too I just can't hear it over the road noise. About 2000 miles ago I got my rear differential assembly swapped out with a junkyard part with only 80k miles on it. It looked good and the mechanic that installed it (whom I trust) said it looked good, but after driving it for a while it appears that I might have sprung a minor leak from where the driveshaft mounts to the differential (I believe this might be the differential pinion seal/?), but I'm not sure if this could be causing the noise itself as the fluid level is fine and it sounds less like a grinding whine and more like a whirring type of wind.

I believe it makes the same noise when turning or going straight, accelerating, decelerating, and coasting (but in gear, I haven't checked if it makes the noise if I shift it to neutral and coast). Additionally, my transmission ran into some issues the other month while I was attempting to move (more info on my prior post) and I have since discovered that the shop I got it rebuilt it at failed to ever adjust the bands properly which resulted in it overheating and creating some nice sparkly glitter in the transmission fluid pan (the magnet was completely coated in debris), so for all I know this might be a noise associated with the transmission? Any ideas?

 

Was it still under warranty? Did you take it back?

 

If it's leaking from the pinion seal, likely the front bearing there is going bad......

 

Check for play at the pinion with truck in N, parking brake set and wheels chocked. You're looking for up/down left/right movement, not rotational (backlash). ANY play is way too much.

 

The part is still under warranty from LKQ, but the mechanic is now 1000 miles away in SoCal so short of ripping it off, sending it back, and potentially getting a "new" one my only option is repair.

 

The front bearing on the pinion shaft can be removed (along with the crush sleeve) without taking everything apart correct? I looked on Rock Auto for the part and it appears there is an inner and outer bearing, but one of them looks to be just a bearing race. I already have it halfway apart right now, wondering if I should go ahead and do that work as well, providing I can?

 

I already have it disassembled to get to remove the seal and inspect the interior, I will check that and report back once it's all buttoned up.

The seal itself looks quite dry, with a bit of cracking so I'm not sure if it's completely shot but the new one I have looks MUCH better. Hoping it's just a worn seal.

 

replacing the inner bearing is an exercise, and requires some pretty specific tools.... which most folks simply don't have. (precision measuring equipment) Replace the outer bearing, and the race, (if you can.... they can be fun to get out....) and the seal, refill, and see what ya get.

 

I just bought the outer bearing, race, and crush sleeve, but to my knowledge I'll have to remove the pinion to get to the crush sleeve? Is replacing it necessary? Additionally, the video I watched showed that to remove the race it appears you need to have the 9.25" gear out as to access the little indentations above/below the race to tap it out. Would I be able to remove it without removing all of the other gears? Differentials are not my strong suit unfortunately...

 

Not sure if you can get it out or not, without complete disassembly.... But, I have changed a fair few outer bearings, without replacing the crush sleeve, just make sure you torque the pinion nut to spec.