Rear axle wheel play and vibration?

[simon barsinister]

Wondering if anyone is knowledgable about how much wheel play there should be in the rear axle.

I'm on my 2nd set of new Michelins after having the first replaced due to two badly out of round tires. I'm having a vibration at all speeds, mostly noticeable between 70-80mph. You can feel it in the seat and center console.

Anyway, I've jacked the truck and placed the rear axle on jackstands and had someone put the truck in drive to observe for vibrating components.
The rear tires seem to oscillate side to side 1/8 inch at the bottom of the tread. I thought this was odd so I rotated the front tires to the back and noticed the same effect.

I'm wondering if this play in the rear axle is normal or may be causing my vibration.

[dyogim]

May need to replace your axle bearings. Worst case scenario a bent axle housing. Try replacing the bearings first.

[DevinSixtySeven]

The rear axle should have no play. Are you sure you're not just seeing the tire mounted funny? Make a note of the high spot, mount a different tire, see if there's a high spot in the same place. If so, your axle shaft may be bent, bearing may be bad, etc...any shop will be able to tell if there's runout at the flange.

-Sean

[simon barsinister]

Originally Posted by DevinSixtySeven

Make a note of the high spot, mount a different tire, see if there's a high spot in the same place.
-Sean

I know my eyes aren't playing tricks on me. I've had two other people observe the same behavior.

Anyone know what's the best & safest way to mark the side of the tire from where it oscillates in and out from the axle? (defect is most visible when tire is spinning in drive)

[dyogim]

When it was on jack stands was their any movement in the wheel/tire other than the rotation?

You could always disconnect the driveshaft from the pinion. This will allow you to spin the tires freely.

[DevinSixtySeven]

Chock front wheels, put rear axle on jackstands. The wheels will be free to rotate through the diff.

Take a piece of chalk, one person rotates the tire, other guy just holds the chalk out, get it closer until it makes a mark on the high side, then stop the wheel with the high side either up or down or whatever, just make sure you remember where it was. Put on the other tire, mark it where the high side should be, test again with the chalk to see if it's wobbling in the same place.

I've done something similar to true bicycle wheels without a truing stand, using a crayon. It's hard to tell how much it's out, but you can tell where it's out.

-Sean

[simon barsinister]

Originally Posted by dyogim

When it was on jack stands was their any movement in the wheel/tire other than the rotation?

None in the wheel/tire; only some small in/out movement of the axleshaft when I removed the wheel. I stopped by the dealer today and they stated some wobble in ALL the tires is not unusual. Don't know if that's true, but I'll try the chalk thing and check if I can see any wobble in the drum itself. I'm open to any other suggestions if anyone has any.