rear axle not aligned?

[whitneyj]

Anyone run into this issue before? Truck's a 95 ECLB dually with 299K miles of mostly towing horses. I have wear on the inside of the tires on the DS and the outside of the tires on the PS. Driving the truck anything faster than 30 feels like being babysat by a British nanny.

I know the hubs are warped on the D80 from a tire shop that installed my wheel spacers without cutting the studs, but that wouldn't cause the odd tire wear.

I'm about to order new center pins, leaf spring bushings, and shackles (for the bushings) but short of a very tweaked frame I'd have no idea. Causes death wobble like you wouldn't believe....

Hints? Pointers? Am I missing something simple?

[stubz616]

Bring it to an alignment shop and get the printout of what's off. It will tell you a lot and where the problem lies

[mike_belben]

i have a hard time believing your hubs are warped. the rear is a d80 chunk but with a D70 style hub. a true D80 wheelhub and axleshaft will not fit into a dodge "d80"

the vibration is likely in the rear driveshaft, midship bearing or univerals. if you dont have a two piece, IE, if someone put in a long single driveshaft for a pulling class or something like that, its surely the issue. look for missing balance weights on the driveshaft too, youll see tack welds. if there are no balance tags,it needs to be balanced. fleetpride can do it as can most big truck frame shops. look at the pinion seal, if its weeping oil, its probably driveshaft.


as for deathwobble, first cause is usually the trackback where it meets the frame. after that will be worn tie rod ends, balljoints, control arm bushings, steering box, steering input shaft and bad lower column bushing. a stabilizer may mask it but thats never the cause. you need a helper to rock the wheel while you get under with a big prybar and see which joints you can wiggle.

[PSUCE]

If the rear axle wasn't aligned wouldn't it still track straight but the truck would be skewed? Have you been drifting Fast and Furious style to cause wear on the right side of all your tires?

On my wife's 1/2 ton, the DS was hit from a previous owner. This caused the axle/wms to be slightly bent. I never noticed it until I followed her one day and noticed the tire has a slight "wobble". It has never caused any tire issues, brake issues, bearing issues, nor driving issues so I have not done anything to fix it in 60k.

[whitneyj]

I have irregular tire wear on the rear wheels. It's not the driveshaft, carrier bearing, or the wheels. I'm aware the hubs aren't true D80 hubs, but I have around a tenth of an inch run out on both rear hubs. The outer rims were replaced by the tire shop that warped them.

The truck does not track straight, it pulls hard right, as evident by the irregular rear tire wear (see my first post as to how they're worn).

The front suspension and steering are all brand new and tight. It's been replaced twice in 10K miles due to the death wobble caused by the rear axle not aligned.

I've gone through this truck from front to rear and the only thing not replaced are the rear suspension bushings and center pins of the rear leaf packs. I have no movement from and of the 6 bushings with a 5' tanker bar, but they're getting replaced regardless.

Not tooting my own horn, but I've been a mechanic/technician for half my life and have a thorough understanding of what causes what. I'm more looking for something people may have experienced out of the ordinary or if they've across this issue.

I'd get the truck on a full alignment rack but that's easier said then done. No one has a rack big enough that'll laser all 4 corners.

What's it take to push a frame rail forward of the other on these trucks? That's what the tape measure shows, but I find that incredibly hard to believe.

[PSUCE]

Seems hard to believe the frame is shifted, without being in a wreck. Is it the PS frame rail that is pushed ahead of the DS? In my head this would make sense based on your tire wear. If the truck is always hooked to a trailer, then the trailer would be pushing the rear and it would want to go left (causing tire wear on the right sides of the tires) which in turn would make the front go right. Does this make sense?

[PSUCE]

Kal Tire lists tread wear and possible causes on their website. One sided wear seems to lend toward the misaligned rear axle.

Kal Tire

[DISTURBED]

Axle tube is bent

[whitneyj]

Originally Posted by PSUCE

Seems hard to believe the frame is shifted, without being in a wreck. Is it the PS frame rail that is pushed ahead of the DS? In my head this would make sense based on your tire wear. If the truck is always hooked to a trailer, then the trailer would be pushing the rear and it would want to go left (causing tire wear on the right sides of the tires) which in turn would make the front go right. Does this make sense?

I was rear ended once by a car, but he hit the hitch square and just folded his hood up. But to my knowledge the truck was never in a wreck. I know the last owner who put 160K of the 254K miles it had when I bought it. She's who pulled trailer with it the entire time time. Trucks had a gooseneck nearly all but a few times there's been a trailer on it.

The tire wear and vibration didn't happen until the new tires went on. It's never done this prior otherwise there wouldn't have been a trailer on it. So this isn't caused from a trailer.

More I think about it when they put the truck on the lift for the new wheels it's possible a bushing anticrush sleeve broke loose and is sitting off center in the bushing. I'd have seen that with the tanker bar flexing things though.

The block and leaves don't show any wear indicating the center pin sheered.

Short of a laser alignment rack how else can I verify the frame is square with the body and power train installed?


That's a good website for explaining tire wear.

[whitneyj]

Originally Posted by DISTURBED

Axle tube is bent

I'd see irregular wear on one set of wheels then, not both sides, correct?

[PSUCE]

Originally Posted by whitneyj

Short of a laser alignment rack how else can I verify the frame is square with the body and power train installed?

One method you could use is with a sharpie and a plumb bob on a concrete floor. Hang the plumb bob from symmetrical points on the frame (center of spring hangers, end of frame rails, etc.) on both sides and mark locations on the floor. Do the same for the axles going from the center of tubes at hubs and at pumpkins. Then mark inner and out frame to get a perpendicular reference. After it is all marked you could pull the truck out and then check all the dimensions for square and pull corner to corner measurements. Crude but would give some insight, I have done this when replacing the rear frame rails on a '66 Mustang that were rotted so I could line everything back up.

[whitneyj]

That's a good idea, I haven't thought of marking the floor. I'll do that once the shop is cleared out.

The body is getting replaced on this truck so it'll be body-less soon. I'll have to inspect the frame once it's off too. Shifted rivets will be a good indication of frame movement.

The rear axle is getting replaced as the truck is getting converted to SRW. I'll have to put the laser level across the axle to check for a bent tube. I can't see a bent tube though, trucks nearly stock minus some tuning and has only hot a few curbs and never really at any speed. (Snow and bald tires)

[whitneyj]

Found the issue with the rear axle not being aligned:
photo 1.jpg

photo 2.jpg

photo 3.jpg

The cast perch actually cracked, came apart, and either powdered/rotted or stuck to the lift block. I've never seen this before on any axle I've worked on.

[95cummins5.9]

Too much salt and too much powwwa.

[whitneyj]

If the stock powertrain was too much power, my other truck had better get linked QUICK.

I fix all my buddy's company's plow and salt trucks, build all their axles/suspension setups, and do all their major fabrication work and I've never seen this on any of their trucks. The only difference on all the salt and plow trucks I work on don't use blocks, they're allllll leaves. Lots of em.

The most common issue I see from salt and leaf springs are the center pins corrode and snap or sheer. So this one is going on the wall.