<VV> Loose pinion gear

[Bill Wells]

John McMahon wtote:
"Hi, everyone.  I have a problem.  My pinion gear is slightly loose on 
the 
shaft. "
 
John,
 
I have rebuilt quite a few diffs. A loose pinion gear is almost always caused by wear on the pinion shaft. You are correct that the gear is much harder than the shaft.
I would not worry about using a new shaft with the old gear, unless you did not have to press the gear on. It should take some effort to get it in place.
On a shaft that had good internal splines, I have used small amounts of JB Weld on the pinion gear splines on  a very clean shaft to ensure no movement by the pinion gear. 
Typically, a failed front pinion bearing will cause a loose gear. Not sure if it is heat or the clearance increase beating it up, but I have only seen loose pinion gears in units that have had a failed bearing at some time.
 
I have never had a failure yet in one I have built to check and see whether the gear loosened up again. 
I will say that for an UltraVan or an FC used to pull loads, I think I would use new gear and shaft or weld the gear to the shaft once shimming was done.
 
Good Luck,
Bill Wells
 
 

		
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