My diff is making a howling noise on accel or decel. I drained the fluid and pulled the inspection cover, and everything looks good. Based on when the noise is being made, we think its the pinion bearings, but I'd like to replace all the bearings for good measure. I called my local mitsu dealer and they couldn't find the part numbers for just the bearings...and the whole unit is $3k.

I don't have time to send it out as I need to get it back in the car by Wednesday, so comments about "send it to so and so" aren't really going to do me any good. One of my sponsors runs a transmission shop, all I'm really looking for is to find part numbers so I can get them FedEx'ed to his shop on Tuesday.

Thanks,

Dave

 

nm

 

We did the screwdriver handle listening trick...def is coming from the rear diff.

 

Bump...trying to keep this on the first page. I can't imagine this is some sort of weird thing to have happen. Anybody else gone thru the same thing?

Part numbers anyone?

Thanks,

Dave

 

Contact TRE... they are the only people other than Shep who may even know what the part numbers are. If you fail to have it fixed locally, send it to TRE, "GEARS" here on Evom. He does this stuff in his sleep.

 

Maybe they've just lost preload? Does mitsu use a crush type spacer on the pinion? I would pull the diff and check the pinion turning torque and compare to the spec.

I wouldn't think the bearings would be bad unless there was another failure in the diff that took them out, but your trans guy probably knows more than me so....

 

Hi ultra revive I researched and found the oem part numbers for the x4 bearings in the rear diff of 8/9. I'm thinking about replacing my bearings while I have diff out to do the lsd restack. I know most people send their big 3 out to places like shep or tre but I just thought this info might be useful to someone since it wasn't ever posted on here.

This part # MB393957 are the x2 bearings on the sides of the lsd requires 2. https://www.rosssport.com/Brands/Mit...-9-MITMB393957

Then there are the front/ rear pinion bearings:
Rear pinion bearing MB393956 https://www.mitsubishipartswarehouse...aring-mb393956
Front pinion bearing MB393955 https://www.mitsubishipartswarehouse...aring-mb393955

 

Replacing bearings is not as simple as just replacing bearings. Pinion depth, ring gear backlash, bearing preload (for the carrier and the pinion), and the wear pattern will have to be setup as if you were rebuilding the diff as the new bearings will not be dimensionally identical to the old ones.

 

This is all true, that's why I was still thinking about replacing the bearings or just simply doing the lsd restack. The more research I did about it the less I wanted to do it lol.

 

The LSD restack is pretty straight forward. I would not mess with the bearings without a good set of tools- dial indicator, press, case spreader (can't measure the preload on the carrier without a case spreader), etc and some experience setting up hypoid gear sets.

 

Well what actually got me to do the restack was a slight oil leak, I noticed a few drop one the floor one day (figured I just needed to reseal the cover). When I pulled the diff it was completely covered in grease, dirt, grim so I have no idea where the leak is coming from (axle, pinion, or cover) but the oil looks like it's dripping from the bottom of the cover. That got me researching diff seals and bearings kinda like a budget refresh. I don't have the $ for a full blown rebuild atm so I think I'm just going to restack and reseal the cover see if that fixes the leak.

Do you know if the pinion gear needs to come out to replace the seal? From the looks of the seal it doesn't have a lip to pry the old one off. https://stmtuned.com/collections/evo...ferential-seal

If I can replace all the seals without disturbing the mesh, backlash, preloads I would go that route.

 

How is the noise? If it is loud or getting worse it needs more than seals.

 

No super loud noises...I do have a slight decel whine kinda hence why I was possibly considering replacing the bearings. The whine isn't really loud at all, I only noticed it when I removed my rear seats.