The '77 Comet I just purchased (For 800 bucks, I might add) just started to take off like a slug through molasses. It feels like it's in third gear when it's in drive, no shifting in to second or from second to third when I'm accelerating. I can manually shift it in to second from the column, and that helps a bit, but when I try to shift in to first it won't go. When it's in drive and I downshift to second it feels like it gets down into the passing gear, but otherwise it won't. I tried replacing the transmission modulator to no effect, so my next idea is to rebuild the valve body, then the transmission itself. Does anyone have any ideas? If it helps, fluid poured out of my tranny when I unplugged the transmission modulator. I don't know if it's supposed to do that or not, but I was told by someone that I may have some valve springs and bearing stuck open, ruining the vacuum in the tranny. Edit: Obviously a new member, my forum search-fu is weak, so if someone already had this problem solved, I apologize.
When you remove the modulator fluid will run out. Did you make sure the valve and pin were in place when you installed the new modulator? Your problem sounds like a bad converter - does the engine rev up but the car accelerates slowly or does the engine stay bogged down when you try to accelerate?
The engine revs slow while accelerating in Drive. But if it's in neutral or park, it revs fine. If I accelerate in second, it's a little better. I can't shift in to first at all.
If it has done this the entire time you have had the car it could be that the linkage needs to be adjusted - for that matter if it just started doing it you may need to adjust your linkage. Does the shifter move into the low gear position? Low gear in drive is using only the forward clutch and if you have second and third you should be able to get low gear. If you have reverse you should be able to get low gear in the manual low gear position.
It just started doing it, actually. I do have reverse, second and drive(for now, third) It won't shift in to first manually, but other than that, my options are Neutral and park. Unless I'm missing something. My car also doesn't drop in to a passing gear from Drive..even when it would have automatically shifted to third.
Check to make sure that the linkage is properly adjusted first. Put the shifter in drive with slight pressure on it toward second. Disconnect the linkage from the transmission (or loosen it) and then tighten it down with no preload in either direction. If that doesn't fix it then It is either a governor problem (sticky valve) or a problem in the valve body. Take the spools out and polish them using 400 grit or finer (a lathe makes it easy but you can use a drill press or hand drill. While you have the valve body out it is a good time to install the TransGo 40-2 kit unless it already has a kit in it.
Well, there's a new development in my problem now, Paul, and I appreciate you being so helpful. The tranny has unstuck itself! Drive is actually shifting...half the time. It starts in first, but sometimes never makes it out of first and just winds up. From what I can gather, it's dependant on how hard I stomp my pedal. Normally smooth acceleration promotes a shift easily from 1-2 and 2-3. But if I try and drop it to low (for passing people...obviously...) it won't shift properly afterwards. Any thoughts?
I would make sure you have a good vacuum source to the modulator valve and like already said make sure the pin behind the modulator valve did not fall out when you changed it. clint
I made sure the pin went back in, and I've replaced the hose attaching to it, maybe the seal isn't tight enough, though. I'll have to jack my car up and take a look at it.
Your C4 won't go into low gear above 25-30 MPH unless the valve body has been modified. If your "kick-down" linkage is set properly it will downshift to second below 55 and to low below 30 MPH just by hammering the throttle to the floor. If you are going to shift it manually then above 30 don't bother going to low - just use second.
Alright, that makes sense. And my tranny is actually working fine right now...I'm not sure what unstuck it. I'm going to go through and check the linkages and things you suggested because it's probably a good thing to do. I appreciate all your help...I'm pretty mechanical, but vehicles are foreign to me. I'm learning slowly
