Rear axle play?

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stewwalker

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I am replacing my rear axle bearings tomorrow and went ahead and pulled the rear tires off tonight to get a head start. I noticed some play in the rear axle, in and out. Is this normal? Play is maybe a 1/8". Do I need to replace the C clips for new ones? Truck has 36,000 on it.
 

matrix243

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I noticed the same thing on mine. Super low duty and wouldn't think would be wore out yet. Noticed probably 1/16" vertical and horizontal. Can't remember if thats normal. I ask cause noticed some uneven wear on rotor.
 

B E N

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End play is normal, with the truck in the air grab at 6 and 12, push hard at the 6 and rotate, should be no noise and smooth. Now with hands at 6 and 12 attempt to rock back and forth, should be no back and forth. If it fails either of these outer wheel bearings are done.
 

CoronaRaptor

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End play is normal, with the truck in the air grab at 6 and 12, push hard at the 6 and rotate, should be no noise and smooth. Now with hands at 6 and 12 attempt to rock back and forth, should be no back and forth. If it fails either of these outer wheel bearings are done.
You lost me here, you say end play is normal, but then you say rock back and forth and there should be none, are you meaning pushing in at the top and pulling on the bottom, type of thing or are you pulling at 6 and 12 and then pushing at 6 and 12 with both hands simultaneously , like you're trying to shake the truck?
 

matrix243

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So pulling in and out slight play is fine, since I think its just play from the axle retainer clip.
For the 6 and 12 you're basically trying to rotate axial, as in rotating your tire, while adding positive pressure at 6. I only rocked mine completely vertical, but I think I wouldn't hear anyting if I rotated. Almost never have had heavy loads or trailer and very load offroad miles, never jumped, 100k miles.
 

B E N

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End play is different, it refers to the axle shaft moving in and out, imagine sticking a dial indicator directly in the path of where you would remove the axle, as you push and pull that number will change. Axial play is normally 10x radial on a tapered bearing.

On a 9.75 the axle rotates in an outer bearing, and an inner bearing. And is retained in the carrier with a circlip. There is no provision for removing the play in the circlip and the spider gear tolerances also show in the end play. So when you stack the inner bearing clearance with the circlip clearance you tend to get some play.

Since the bearings do not retain the axle (unlike say a ford 9" where the bearing holds the axle into the carrier) end play has very little to do with bearing clearance. The conical bearings in the unit would have to be completely wasted to affect end play.

Rocking top to bottom implies that outer bearing is smoked, tolerances have opened due to wear or mis-adjustment.

I haven't seen much damage on the outer bearings on these, you do see the pinion bearings get eaten though, especially in blower and big tire applications. When the pinion bearing starts to wear heavily those hardened steel shavings go into the oil and the magnetic plug loads up the shavings are transferred to the entire axle assembly, usually results in a full rebuild. So if you have noises pull the plug and look for metal.
 
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B E N

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Diagrams look fine to me.
Third would be an arc on the right hand side going up and down, imagine that outer bearing were completely missing, that's the dramatic version
 
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