I had a rebuilt Auto tranny installed about 7 months ago and have less than 2,000 miles put on it.  Now that I've moved to hill country, when going up hill I get a strange feeling from the rear end.  Its sort of a feeling the the power going to the rear wheels lets go and then reengages within a half-second or so. It may do this "trick" only once or it could be continuous - almost to the point of having to pull over. This problem only seems to occur going up hills and doesn't seem to matter if its warm or cold.

Any suggestions?  I see no dripping tranny oil.  Could this rebuilt tranny need adjustment?

Thanks in advance.

Ed