1977 c-4 Trany into 1974 My 1974 Maverick is slipping I have a c4 out of a 1977 maverick. Are the tranys the same. On the 77 the vaccum has two hoses on the 74 it only has one / Whats the deal Dean
The c4's are the same. The vaccum lines are coming from the modulator. I think in 1975 they went with 2 lines suppose to be to bring the tranny gas back in the engine to burn. More polluation junk on the engine. anyway use the one it wouldn't hurt. Block the vaccum link going into the engine and you will be set. I had my tranny rebuilt and they replace my dual mod with a single. I hope this helps.
modulator i think you can use whichever one fits your needs, i heard that the second line was for shifting low at cold temps to warm the engine up faster. either way you can swap them out for whatever you want to use. i've done it with a '78 c4. it seemed to work fine.
One thing you may run into... the 77 tranny may have a larger bellhousing on it. If so you can just swap the one from the 74 tranny onto it and use that torque converter as well. Alternatively, you can keep the large bell and swap to a 164 tooth flexplate, but that involves buying things.
