Need some real help here. I have a 72 Mav/302 with original C4 and 110,000 on it. I have 1st in D but nothing else. I can shift manually through 1st and 2nd but when put in D it drops back to 1st. Have replaced the Modulator with one with a white stripe... Is that the right one? have great vacuum also. Next thing to do is drop pan for filter change and check there. Any suggestions on what it could be? also when shifted manually into 2nd it kinda studders for a second when accelerating but accels fine when WOT . Any help would be AWESOME!
So i canged the fluid and filter. Fluid was bright pink so i'm guessing thats a presence of water. still no shift in Drive and has a sputtering pause when trying to go WOT only in drive.
Does it shift into drive but not do anything? Or it won't go into drive? If it does, and doesn't do anything..then you better find a transmission shop. If it doesn't then it could be a linkage issue.
it shifts into drive but will not shift out of first gear no matter if i use light acelleration or WOT. But i can shift from manual 1 and into 2 and it will hit second but when i put it in drive it drops back to first gear
yes. checked all lines and replaced all the rubber and modulator. i have between 12 and 15lbs vacuum when idleing at the modulator.
Orig C4 are prone to break the 2nd gear band, so only have 1st & 3rd... You can try adjusting the intermediate band, adj is just ahead of the manual linkage... To adj loosen lock nut and turn the adj till it starts getting snug(actual spec is 10ft pounds but snug is fine) then back off 1¾ turn, tighten lock nut while holding the adj bolt steady... If the band is broken the adj will just keep screwing into the trans, so if you've turned it say three turns and it isn't getting snug that's likely the problem... Occasionally they can get so far out of adjustment the band anchor falls out of place(happens when band broken as well) and most of the time it will jamb the manual linkage when it drops down on the valve body, preventing shift into park...
I adjusted the bands to specs this morning before changing fluids and filter. Intermediate band seems quite worn as i can screw bolt almost down to the end of the threads (3/8IN or so) before i hit 10 ft lbs, but still got it to adjust. It has every gear and goes into every gear without a hitch, just doesnt come outta first in D. I've read up on it alot before i posted this to try and figure it out. The only thing i havent done is air checked the govener or the valve body as i dont know much about auto trannys.
It's operating frely and adjusted to where it doesnt engage until WOT. I'm starting to wonder if something in the valve body might be rusted and stuck. It set for a few years before i picked it up and it did have water inside the case...?
Is it possible to pull the VB out without pulling the tranny and without losing any ball bearings or anything else out of the transmission?
Yup. Before I did that I would pull the modulator back out to make sure the pin is still in there and not stuck. Did this just start happening all of the sudden?
