[sunflower100]

How much play in the rear axle shafts (from side to side and up and down) when I have the rear-end jacked up, both wheels off the ground. I had the differential cover off and inspected the gears. Put a dial indicator on the bottom side of the Ring gear teeth in three places and got .010 backlash, but I didn't have the driveshaft disconnected, just turned the ring gear by hand. Was this the right way to check this? I have about 1/4 inch play both sides up and down on the axles and can move them in and out 1/4". What is the allowed slop? Side to side they were pretty tight.

I am getting a howling noise when giving it gas between 40MPH and 55Mph. it stops when I let off the gas. Coming from behind somewhere. I also am noticing the vehicle shakes noticably when vehicle is under load in Lockup. Any ideas?

[mgfg]

This must be on a p/u truck>>>>I've never seen a diff cover on a class 8 truck.

1/4 inch of movement sounds like a lot to me, 10 thou of backlash isn't much.

[mike in idaho]

Backlash sounds about right for used gears. Any slack in the bearings? Put a prybar between the housing and the ring gear and pry up and down, side to side to see if there's any movement. Check the pinion shaft for looseness by shaking it sideways, fore and aft. The pinion & side bearings should have some preload, any looseness means it's time for bearings.