Trying to evaluate a second hand diff I bought as a spare. Spun smooth from the front but couldn't get the outputs to spin with the input locked. I assume this should be easily done by hand but I ask because I have much less leverage than when I have done this on the car using a wheel. Went ahead and opened it up figuring the inside would be toast but the ring and pinion look great and no debris to be found. So questions,
Did I fail the diff test or is is it not possible to check it by hand at the outputs?
If it is bad can I disassemble it to check for debris? I keep seeing that you can't take them apart but other than keeping things in proper places it doesn't seem all that complicated? Am I wrong?

Thanks,

John

 

-do not take it apart, as any change in the backlash will cause the R&P to whine
-with input locked, one output should turn free, while the other turns in the opposite direction
-if yours doesn’t, it does not mean the dif will not function properly in the car
-put it in the car and run it

 

So even though it fails the test it might still be OK. That's worth a chance. I will seal it back up and stash it for when I need it.

Thanks

 

Correct, the LSD units can become sticky. You will likely get a thumping noise, when coasting during very tight turns, such as parking lot maneuvers. It will operate fine on road and track.