Thread: 400 won't shift

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bought a project truck that has a built 350 and th400. transmission never really worked right, slow to shift, but it did shift. now it won't shift outta 1st at all. the vacuum line was loose and leaking so i rehosed it. it's hooked up to the back of the q jet to a diaphragm. i'm not much of a trans guy obviously. can i shift it into high manually to get it to the shop if i have to? it also has developed a little slip. i know it's probably toast but i'd like to band aid it 'til the slush fund can support a 700. thanx, rick

Make sure the modulator is hooked to a manifold vacuum and not a port vacuum...this means that it will have suction on the hose anytime it's running...Needs to be at the very bottom of the carb or hooked directly to the manifold...There's also governor that can be checked and/or replaced without pulling the trans. It's under a plate on the side of the case..

thanx daffy. the vacuum line is hooked up to a diaphragm port high up on the bavk of the carb. ill connect it to full manifold vacuum and see if it'll shift. thanx again

ok, i hooked the trans up to the big vacuum port on the front of the carb and the trans shifted flawlessly. the distributor is hooked to the small ported vacuum on the front of the carb. does the pcv valve connect to the big port on the front of the carb. i tested it for vacuum and there was none. right now the pcv is teed w/ the brake booster directly into the intake manifold, thanx, rick

Pcv should be OK...It runs off manifold vacuum as well...Glad the trans worked out for you Advance runs off port Vacuum so that's correct too