Need Help Finding Cause Of Wear in 92 Astro Van Differential
 

I need help understanding what would cause the C-Washer Wear and the wear of the Splines on the Left Axle; that seems to have slightly narrower splines at the inner end.
1992 Chevy Astro Van Rear Wheel Drive 7.625 Ring Gear (wear there OK).

The C-washer is from the Left Side.

The Side Gear wit the Groove where the C-washer rides is from the Left Side.

Both of the Differential Carrier Bearings show a Dark Grey Wear area that looks as if it ran over some small particles and the Rollers have some scoring but nothing catastrophic that would pull the Carrier out of alignment.

The area where the C-washer rides in the Right Side Gear is perfect.

I forgot to put this in the first Post. The Van came with a Tow Bar attached so the Prior Owner towed something. Bought it from a Used Car Lot so I have no History on the Vehicle.

I Pulled the Axles as I had a right side Oil Seal Leak and had only planned to change the Oil Seals; till I saw that C-washer and big pit in the Side Gear.

The right Side gear has one large Pit like it squashed something and there is some areas around the bottom of the teeth that show that it was wearing through.

It could be just the way I am viewing it but the Left Axle seems to have thinner splines and more so towards the inner end than the Right Axle does.

The Spider Gear Shaft had some wear but did not look abnormal (no pic of that)

The Left Axle Bearing area has some fine scoring that the Right Axle does not have. Both have a kind of gray wear area. The Bearing rollers also had that gray lapped color look.

Pics of the Carrier Bearing Races and one of the Axle Bearings.

Did it run a long period with different rolling diameter tires on the rear?

It had new Tires that were all the same size/diameter when I bought it about 10 years ago. Only last Month did I change the Tires; when I discovered the Seal Leak.
The Tires still had decent Tread but the sidewalls on 2 of them were cracking.

It drives mostly around town and I don't drive it a lot. I have never towed anything with it.

Just like with Mercedes We don't know what the Prior Owner Did.

Due to the Oil Seal leak it could have been low on Differential Oil.

Going along with the above comment. I read on one of the Chevy Van Forums that the different diameter Tires would cause what was phrased as "pop the left axle out".

What I am wondering about is if your Rear Brakes were out of adjustment and one side was breaking more than the other would that cause the same type of Wear on the C-Washer.

The Rear Brakes are supposed to be self adjusting but they don't.

That's an interesting question Diesel.

If it were mechanical brakes then I would tend to think it would be possible to see some C Clip wear if the brakes were out of adjustment, but with hydraulic brakes the pressure on both sides will be basically the same, it's just that one side will drag before the other travels far enough to make equal contact and start building brake system pressure. At that point, when there is meaningful pressure, it would be equal on both sides.

Have you already come up with some side gears or a replacement diff unit?

I guess I will blame it on the Prior Owner!

Since it is not a Mercedes I am going cheap; am guessing the Motive Gear set is made in China.
This Van drives around Town and occasionally to LA no more then 20 miles in one direction. I have never towed anything and have no plans to do so.

I bought all of the below stuff from eBay with Free shipping and am still waiting on some to arrive. I already have the parts in Blue and am waiting for the rest.
1 each Motive Gear GM7.6BI Gear Kit total cost $102.50 eBay
2 each Torrington US Axle Bearings total cost$32 (exactly the same as I removed from the axle) total cost $30
2 each AC Delco Axle Seals total cost $12
2 AC Delco Carrier Bearings Timken USA total cost $25

The Pinion Seal has also been leaking but not like the Axle Seal Was. I was supposed to drop the Driveshaft to day and get the Number off of the Seal but did not get to that. Will be ordering more parts.

If you have some part numbers to start shopping with (you can eventually cross reference them to other companies numbers) you can get the good quality Bearings and so on at a fraction of the Price on eBay.

And, of course like the rest of the Job one thing leads to another. Besides the Pinion Gear Seal the rear Transmission Seal leaks and since one end of the Drive Shaft will be coming off I guess that other end is also to fix the Trans Seal Leak.
May do the U-joints also.

One seller on ebay is selling Despite the description this is a complet New Limited Slip type Differential Carrier.



Chevy S10 S15 Astro Safari Rear Axle Differential NEW!!

$249+$23 shipping.

I thought about that but I have no particular need for the a limited slip Differential and I have never had to go this far working on a Differential before.
I may or may not be changing the Pinion Gear Bearings.

I have the real Chevy Service Manual for My Year and Model of Van (parts book to) but the description of the rebuild is kind of sketchy and there is a need little Tool for help with setting the Carrier Preload I do not have.

I am hoping that by buying the exact Same Carrier Bearings I will not need to mess with the Carrier preload.
I have Micrometers and Dial Indicators and so on and when I get the New Bearings I can measure their thickness to see if they are the same dimensions.

The Pinion Gear has a similar Crush Sleeve arrangement as the Mercedes to set the Bearing Preload.
I suppose if I have to change the Bearings I can use a Depth Mike to check the Original Height/Protrusion of the Pinion Gear into the Differential but I don't have the Tools listed in the Manual for that.

I'm not intimately familiar with that particular diff. I've e done a number of nine inch Fords and few 8.8's. As long as you get the pattern and backlash correct, you should be okay.

I learned how to set them up from a video tape over 20 years ago. If you've never done that particular axle type, I expect you can find a YouTube or ten that will help a lot.

I say all this and you may very well have more axle experience than myself, so no offense meant.

I think the motive gear set will be fine as long as you set it up right. You might use synthetic lube too. It's expensive, but nowadays I use it in almost everything.

Good luck

When I was a Diesel Mechanic I worked on Fuel Injection and Engines. In fact most of the Engines turned Generators.

I have never ever been this far into a Differential. My only previous experience is with Changing Axles and the Bearings.

The only 2 hang-ups I can see are the Carrier Bearing Preload and if I removed the Pinion Gear the Pinion Gear Height.
But, I believe I can take the height of the Pinion Gear before I pull it and replace it to the same height
With the Carrier Bearings it has the one original Cast Iron Spacer on each end. Meaning no one has been inside and replace the Spacers with a Shim Pack.
If need be I can re-do the Gear back lash as I have experience doing that on other stuff.

one thing to check after you get all done is the vent.

It looks to me like the adjustment is / was all out of whack.

The wear marks on the bearings isn't quite where I'd expect to see them

http://www.peachparts.com/shopforum/...race-right.jpg

Ideally the bearings should be running in the middle of the cup not kind of on the outer edge as shown in the picture. I'd expect to see them further in a bit.

I guess it was all a bit loose and that's how the clip got worn.

Not if one caliper isn't traveling the full amount or stuck.

I wonder what would happen if the axle housing was bent by running over a big rock?

Those rear ends are garbage. Chevy puts them under anything from Astros to z71s.

I've replaced plenty. I would junk it and get another one for 200 bucks. Change the fluid and drive it.

FYI- I've seen a trend with r&p's. pretty much all after market ones I've installed (or co-workers did) made some sort of noise. Properly set up and everything. Brands like Yukon and others. The factory ones either new or used were the ones that didn't make noise. Just a tidbit of info.