The forty to fifty mph issue is common with that transmission, it is the gearing in the transmission, and vehicle that give it a "dead spot" at the rpm range for those speeds. Mine has done it from day one.
The poor take off and reverse issues sound like the transmission, is low on fluid. If it is in the normal range then it is slipping and it is time for a rebuild (or a re-man transmission, ).
I would also suggest adding a larger cooler if you rebuild, these transmissions really hate heat.
Friday, July 14th, 2017 AT 2:05 PM