Only drives in reverse

Not all parts of a transmission fail at one time. There are still plenty of good mechanics who can quickly evaluate your tranny and price out the differences in reliability between a new, a rebuilt and a partially rebuilt tranny. I had a similar situation, opted for a rebuilt, paid less than $1500 with a local mechanic, but hold bids from single purpose tranny shops at $6,000 and a lot more than that from two different Jaguar dealerships. Be patient, ask around, look for a very busy shop, they are busy for a reason.