rear diff kaput?

[jesse]

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    I was under my '86 4K changing the fuel filter and started checking out=
 some of the rear bits while i had it in the air.  I noticed what seemed to=
 be a fair amount of slop in the rear drive train.  Mainly i would turn one=
 tire and there would be a bit before the opposite side would start to spin=
.  How far should you be able to move one tire before the other starts to m=
ove?  On the same note i have had a *klunk* that sounds like it's coming fr=
om the rear whenever power is applied.  Could this be a dying rear diff??

    If so, where is a good source for a reliable unit?

Again, thank you,
-Jesse Erickson
Rochester, MN
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