Ford Repair: Transmission Problem, vacuum problem, shift linkage

Question
I have a 1974 351C with a rebuilt transmission, C4, won't shift into third at all and will only shift from first when the selector is in second. Has good vacuum at trans module but engine seems to be having carbuerator problems when in gear (won't idle and generally runs bad at lower RPM's) Did not have this problem before the trans blew all foward gears. Tranny shop says I have a vacuum problem but I can't figure out how.

Answer
MICHELLE


it could be many things.check the modulater vacuum line all the way to the motor.check the modulater control rod for sticking.the valve body for sticking valves.the clutch bands out of adjustment.check the shift linkage to see if its adjusted right.when you say it will shift from first whrn selector is in second tells me the linkage is out of adjustment or the trans shop or who rebuilt the trans do not have the bands adjusted correctly.the rough idle sounds like a vacuum leak.hope this helps.

ken