[Coreyterry]

im having problems with my transmission, its a th400. when it goes to shift from 2nd to 3rd its slips. but it only slips when the rpms are low. when i puut my foot down it shifts fine. i changed the modulator valve and it helped a little bit. also when i manually shift from 2nd to 3rd its shifts fine. what i was wondering is if there is suppost to be a passing gear on the 400s? if this is even the problem then thats great but if someone might know what exactly it is then i would be happy to know.