I don't agree that the 8 3/4 would be marginal, especially with an auto.

HOWEVER, if you are going to buy a new rear anyway, why not just spend the extra and put the D60 in, then no matter what you may eventually do, the rear is done. In the long run it may very well be cheaper.

They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.