Soooo...appears that the left rear wheel / axle bearing has gone bad all of a sudden; very noisy, just sounds terrible!

Any suggestions for bearings/seals? Of course going to do both sides. And this would be for my '02 4dr 4wd.

I will have to borrow/rent a tool to remove the seals / bearings; slide hammer or puller....one of the two...hope not to have to buy one.

And gee....I had replaced the diff fluid, cover, seal just about a year ago....oh well...such is life.

 

Watch some youtube videos, but it sounds like you know what you're doing. I have not done the bearings on a Blazer, but have done them on a Tahoe and I think they're the same rear end. It was very difficult to get the bearings out, even with the slide hammer and the three piece puller set. I wound up breaking one of the races (it just shattered). I don't think the pivoting puller in the kit was quite the right size, so it didn't engage the race fully. It was a lot easier on the Fords I've done and I couldn't tell you why except that the tool might fit those bearings slightly better. And make sure to use the full stroke of the slide hammer. I was confined for space and wasn't using the full travel of the slide which might have made my problem worse.

The only other thing I'd say is to make certain that its your wheel bearing making the noise and not a pinion bearing or something else internal to the differential.. On my Tahoe, the pinion bearing was bad. I jacked the car up and put it in gear and listened to different parts of the rear end with a Harbor Freight mechanic's stethoscope.

Also in installing the new bearings, I'd rent the bearing installer kit and use big hammer (3-4#) to drive them in. I found that this combination made things go in easy.

Lastly, that thin bolt that holds the C-clips of the axles in (internal in the differential) is supposed to be replaced. I has not happened to me, but I've read where people snap it off taking it out. So obviously make sure you have the correct fitting socket (I believe 8mm) and be careful if it doesn't come out fairly easy. its locktited from the factory, but mine have all come out with a 1/4 ratchet.

 

I am 99.9% sure it is the wheel bearing, can feel and hear it when I rotate the axle, plus the movement (up/down, side to side). Hopefully the axle is not damaged.

I will head your advice about the small bolt that holds the pin in.

I have a bearing installer or I could use the old bearing to install.

Going to be renting the axle bearing removal tool from O'Reilly's Auto Parts, hopefully that will work.

Not going to be doing the job until mid next week when the parts arrive.

Thanks

 

Upon further inspection there seems to be excess backlash between the pinion and ring gear, although I have not opened the diff yet to actually check the pattern.

I was looking at GM 8.5" diff rebuild kits and have to admit that I am confused as they show 4 bearings. I though there were only 3 bearings....what am I missing???

 

The pinion has two bearings and the outer side gears have one each. This is a common differential and there are a lot of rebuild videos. Ford's are very similar too. There's a lot involved with shims and setting pinion depth and backlash. For simply not having to go through the learning curve, I'd consider replacing the whole rear end with a junk yard unit. If you choose to rebuild, try to watch some of the more competent guys on YouTube. There was a professional video when I did mine, but it got taken down unfortunately. There are also a bunch of written materials on the web .I believe I bought Yukon brand (repackaged) bearings. They came with general instructions. You've also got a crush sleeve to install. Buy some extras if you crush it too much. You'll also need a beam style inch pound torque wrench. It's messing with the shims to get the pinion depth correct that can drive you crazy. You will also need a press and bearing separators.

Here's a video on a Ford from Eric the car guy. I don't care for his stuff much, but it probably better than most for an overview. https://youtu.be/Plvg0NTLraA

Look for the gm 10 bolt videos. That seems to be a more commonly used title than 8.5 inch.

 

The pinion has two bearings?...really?...as I have been viewing several videos on GM's 8.5" and not a one of them showed two pinion bearings...makes me wonder.

However you must be correct as the rebuild kits have two pinion bearings along with the two carrier bearings.

I will check the backlash and attempt to determine if the pinion bearings have excess movement in them. Most likely I will just replace the wheel/axle bearings and seals, call it "good" and leave well enough alone.

I am wondering what caused the left wheel/axle bearing to become so noisy so quickly. I did put 1" spacers on the rear about two years ago, perhaps this is the cause...IDK.

 

There is an inner pinion bearing pressed on the pinion shaft by the gear and an outer bearing that installs onto the shaft from the outside by the yoke.

 

Finally got the diff cover off yesterday, axles out, seals and bearings removed; the left one is just worn and noisy, do not know why.
I thought the 4d 4wd Blazers had the 8.5" ring gear, but nope, it is the 7.625" ring; ordered the wrong bearings/seals, so will have to wait a few days for the correct parts to arrive.

Gives me time to see if I can find a used, working G80 carrier to swap. I looked at new posi carriers, but just not able to justify the cost.

And thanks for the info on the two pinion bearings; I will see this should I remove the carrier and do the G80 swap.