Replacing rear bearing advice

[DIYguy]

Hi all
I had that dreaded rumbling “wind noise” sound which started at 25mph… it got quiet turning/banking left and stayed loud when turning/banking right at speed so I narrowed down to the driver side…. Jacked up the car and front hub was tight but rear wheel could slightly rock at 12-6 position with an audible clicking sound….

So it looks like I’ll be replacing my rear wheel bearing and seal.

I read the how to post and watched some videos so I’m fine with the process but looking for advice on a couple points…

1. Is there a benefit to replace both rear bearings at the same time? I know I can just replace the 1 ok and the only real savings would be the differential fluid and small time savings related to that step so I’m inclined to leave the other alone for now.

2. Is there a preferred brand of differential fluid that has worked well in our vehicles or “anything” meeting the gear lube spec in the manual is ok

3. Would you go with a replacement differential cover gasket or use an RTV type gasket maker?

Thanks in advance

 

[Mooseman]

1. Is there a benefit to replace both rear bearings at the same time? I know I can just replace the 1 ok and the only real savings would be the differential fluid and small time savings related to that step so I’m inclined to leave the other alone for now.

There are no savings as you have to open up the diff to remove the axle so you lose all your fluid anyway. Might as well do the other.

2. Is there a preferred brand of differential fluid that has worked well in our vehicles or “anything” meeting the gear lube spec in the manual is ok

Any 75w90 synthetic axle lube will work. Not sure if Ascenders came with the G80 locker or G86 limited slip. Check your RPO codes in the glove box. If you have a G86 limited slip, get lube that has the additive already in it. If it's a G80 or neither (open diff), the additive doesn't matter.

3. Would you go with a replacement differential cover gasket or use an RTV type gasket maker?

Personally, I prefer the rubber cover gasket as it's reusable and makes it easy for future lube replacement. The RTV is a PITA to remove but is a popular choice.

 

[Mooseman]

Also be forewarned that the axle itself might also be damaged with the bearing wearing a groove into the axle. You would have to source another axle to replace it.

 

[DIYguy]

Also be forewarned that the axle itself might also be damaged with the bearing wearing a groove into the axle. You would have to source another axle to replace it.

Thanks. I’ll check for that. I saw there are “repair bearings” that have a built in seal and so it shifts the bearing position slightly to sit on the axle offset from where the wear may be, allowing reuse of a scored/worn axle.

 

[DIYguy]

There are no savings as you have to open up the diff to remove the axle so you lose all your fluid anyway. Might as well do the other.


Any 75w90 synthetic axle lube will work. Not sure if Ascenders came with the G80 locker or G86 limited slip. Check your RPO codes in the glove box. If you have a G86 limited slip, get lube that has the additive already in it. If it's a G80 or neither (open diff), the additive doesn't matter.


Personally, I prefer the rubber cover gasket as it's reusable and makes it easy for future lube replacement. The RTV is a PITA to remove but is a popular choice.

GU6… so I have the standard open 3.42

I’ll make sure to get one that says it includes additives for differential lube.

 

[Mooseman]

I've used one of those repair bearings and I'm not a fan. It worked but it pushed the seal out to an unused and rusty portion of the axle and made it harder to remove and insert the axle retaining C-clip because if the extended seal. Turns the axle removal/install into a two person job with one pushing on the axle and the other pulling the C-clip. And it's a sealed bearing with grease as a lubricant that can't be replenished easily. And if you have to remove that bearing, good luck!

 

[DIYguy]

Replacement of both rear bearings went great last weekend… Differential fluid needed changing anyway. I used National Bearings from advance auto and was glad to see they were made in the USA.

I took it on a short drive in the neighborhood and it drove fine.

But when I drove again this week to work I noticed the rumbling still

I did the “swerve” test going 30-45mph and rumbling goes away veering left but stays when veering right consistently. So now I’m thinking it must have been the driver wheel hub all along (and there might have been some play I didn’t notice).

Does that sound like the right diagnosis or any other thoughts?

I’m leaning toward ordering a pair of hubs from Detroit axle and just do both and be done with it.

Still, I’m glad that I replaced the rear bearings as there was definitely up/down movement there and I caught it before extensive wear/damage to the axle…

 

[Mooseman]

I did the “swerve” test going 30-45mph and rumbling goes away veering left but stays when veering right consistently. So now I’m thinking it must have been the driver wheel hub all along (and there might have been some play I didn’t notice).

Lots of guys have been burned by that test. Best way is to jack it up and spin both sides. If you can't tell the difference, may need a mechanic's stethoscope or use a long screwdriver to your ear while spinning the wheel.

I’m leaning toward ordering a pair of hubs from Detroit axle and just do both and be done with it.

Good choice . If one is dead, likely the other one isn't too far behind.

Once the hubs are off, you can spin them by hand and tell which is noisy.