>I have a used diff of unknown parentage and I was wondering if there was
>an easy way to find out whether it was worth trying to use or not. I know
>I could put it on the car and find out that way, but I'm looking for a
>quick-and-dirty test (or tests) that I can do to at least see if it's
>worth installing or >not.
>Any ideas are welcome!
Dave's advise is good, in addition, measure the rotational backlash.
Make a mark on the input flange and rock the flange left and right until
the output flanges begin to move. Actually, you can "feel" the contact with
the gears inside. Alternately, you can have an accomplice hold the output
flanges so you can turn the input flange and note the internal "play". I do
not know of any published specifications, but my experience with my
Spitfire is that a nice "tight" differential (rebuilt from Rimmer Brothers
by way of Victoria British) measured about .02" while the transmission it
replaced measured about .15" shortly after I bought the car (and lasted
nearly two years before "howling" and another two months in use before
self-destruction took place.
best regards, John Pratchios '80 Spitfire, Daily driver