Crazy C4 Problem

[TURBOMONT]

We have a C4 of unknown orgin that we put into a car. It is supposed to be a reverse manual valve body and when you shift it reverse it will go into second gear but not into high gear. Now to throw a curve into the mix, the trans had a vacuum modulator hooked up, but we did not hook up the vacuum lime because it is manual. If you do hook up the vacuum line, it will not shift manually at all but will shift automatically and it has high gear. It will not shift foward at all. hmmmmmmmm. I haveno idea, and one out there have any kind of a clue as to what is wrong. The trans is full of fluid and the shifter is adjusted correctly also.

 

[Sean124]

We have a C4 of unknown orgin that we put into a car. It is supposed to be a reverse manual valve body and when you shift it reverse it will go into second gear but not into high gear. Now to throw a curve into the mix, the trans had a vacuum modulator hooked up, but we did not hook up the vacuum lime because it is manual. If you do hook up the vacuum line, it will not shift manually at all but will shift automatically and it has high gear. It will not shift foward at all. hmmmmmmmm. I haveno idea, and one out there have any kind of a clue as to what is wrong. The trans is full of fluid and the shifter is adjusted correctly also.

Hmmm sounds like it could be a normal valve body. The behavior is odd. Most of the older automatics did have a pretty crude manual function built in. My advice would be to take it to a trans shop.

 

[TURBOMONT]

I know, but if it was normal, 1st gear would not be right after neutral. The pattern is correct for a manual, PRN12?

 

[orangejuiced86]

are you sure the shifter is adjusted correctly? I just fixed the same issue on my car.

 

[TURBOMONT]

You had the exact same problem. We went over the shifter 10 times, what is crazy is thefact that it will shift automatically with the vacuum hooked up, no matter what position the shifter is in. But will shift manually (reverse pattern without high gear) if the vacuum is off.

 

[TRBOBUICK]

You got fucked.....its a regular VB.

 

[TURBOMONT]

Hey thanks, but why does it shift p-r-n-1-2-?. If it was a regular, it would not shift manually from drive to 2nd, would it? It does not shift if I move the shifter forward.

 

[TRBOBUICK]

I dunno, fatman. Just go with a th400 and be done with it.

 

[orangejuiced86]

if its a normal valvebody when you put it the first gear after nuetral it will end up in third, but start off in first.

 

[90_Notch]

You got fucked.....its a regular VB.

Yep regular VB. I know a guy who builds his own VB if yea need a good trans guy let me know he's my brother-in-law he's very good and has some great prices. Build some badass transmissions. Does alot of work for alot of racers, he's just north of sterling heights.