Unusual cupping right, rear drive. What's causing this?

Well I don't know if it's your problem but those wear pads absolutely are supposed to be on there.

I'm really surprised you had six alignments and no one thought to do that.

Those wear pads stop the spring from hitting the hanger.

I don't know that it would cause your problem but those wear pads do limit how far the spring can actually move.

Check your hangers to make sure they are not broken or cracked.

Here are some old ones. You can see how they wore.

 

I had the dealer check alignment plus 3 other shops until the one shop fixed the issue

 

@6cuda6, I have the bushing style of torque rod. I've had this truck for about a year and it came with Hankook DH06 tires, which I had regrooved. Got 6 extra months out of them but the tires on that rear axle wore out twice as fast as the other drives. Then I put on used Michelin XDN2 but they wore out after 2 months. Then I got some recaps from a guy on craigslist but thr outer tire blew out on that axle and the inner one was worn on the edges so then I put 4 Hankook DL11 on the back axle about a month ago. The inner tire had a 3/8" bolt go through it so the shop installed the used tire that's on there now. The left side still has the DL11 and they are holding up well. No funny wear.

@Dino soar, you and magoo68 are right. I am going to get the wear pads installed ASAP.

This forum is great. Good, compotent mechanics are hard to find but this forum helps a lot. Thanks for your advice.

 

It is possible that the axle housing is bent. The easiest way to check is to remove the differential carrier and install and tighten the axles. If the inboard ends of the axles don't align perfectly the housing is bent.

 

It is possible but if so the alignment(s) would have picked it up.

 

Call Mike Beckett at MD alignment out. He can tell you exactly what is wrong.

 

I think the tires just already started a pattern, and is getting worse quick. Bad shocks, low air, being mounted next to a larger diameter tire, all can cause or contribute to it. I call it step wear. Heel to toe, same thing. Used to g et it a lot running I 94, due to washboard road, worn shocks.

 

If the equipment that they used to align the rear axles used the
center drill holes in the ends of the axle flanges they would not catch a bent axle housing.

 

Follow up to this thread.

I bought new shims (they cost about $8 each) and was at the shop when the mechanic says "well, look at this !"...

Turns out, the truck has the shims already but they are hard to see from the outside. They are underneath the spring.

So I'm back to figuring out what's wrong with that axle.

I will call Mike at MD Alignment today.