Play in Rear

[angelo49]

2002 xlt
Have the common whine/hum in the rear, and going by info from another thread, figured I'd change the oil and see if it would change anything.
Jacked it up , got under to see what tools I needed.
Coming out from under the truck I put my hand on the rear wheel and it turned quite a bit, without the drive shaft/yoke movingat all.
Moves from 12:00 to 2:00 And yes, I do get a clunk when shifting from drive to reverse.
Poster black92LX mentioned its time for a rebuild and I guess he's right.
Anyway, how much play, if any, should there be?
Angelo

 

[IZwack]

Thats somewhat excessive but its not a true test of how the ring and pinion gears are meshing because there are intermediate parts that also normally have "play" in them -- like the spider gears.

I think a better test is to disconnect the rear driveshaft from the axle's input flange and push up/down on the flange -- any play in that direction is definitely a cause for concern. Rotational "play" is called "backlash" and a few degrees of this rotation is normal.

 

[angelo49]

Well,
I changed the rear diff oil, but it didn't help any.
Put Mobil 75-140 Synthetic and friction modifier, but that whine/hum is as loud as ever.
I'm going to get someone take a look at it this week.
Angelo