Like the title says. I can live with 1st and 3rd for a while if I have to, it runs fine just has no getup and go. Shifts smooth though. If I put it in 2nd it shifts 1st to 2nd fine. But in drive it goes straight from 1st to 3rd. The fluid level is fine. Are there any other things I should look at before thinking about swapping a new tranny in there? I have a 200c.i. If I put another tranny in is there anything I will have to be aware of? I.e. do I have to worry about getting a C4 from an 8cyl? I know the bell housing won't bolt up but I assume I can keep my bell housing and bolt that to the tranny. I also have an AOD in the garage that was going to go in my Mustang. Dunno if that would work on this... Odds are though, I'll probably go with another C4 if I swap it. Jason
I've got the same problem. If I shift my car manually (using 2nd) it is a lot quicker, but I don't really like to bother. If it hangs tough through the season, mine will come out next winter for a rebuild. Good luck.
You might try a modulator valve.(pretty sure I spelled that wrong). Its located on the passenger side of the trans and there is a vac. line attached to it. Make sure you have pan under it when you change it. My parts guy asked me to bring my old one in so he could make sure he gave me the right one. Its like 20.00 bucks so no big loss if fails to fix the problem. You might even check to make sure the line has not come loose at the valve or the manifold. Just a thought.. Jerry
Is it doing this at full throttle? If you are driving at very light throttle, it might be launching in second and going to third.
It doesn't go into 2nd at any throttle level, light or wot. I read about the vacuum modulator last night and I read the shop manual to figure out what tests I can do on it. It sounds like that could do it so I'm going to look at it this week sometime. It would be nice if that were the culprit. Just an interesting sidenote though... I went on Autozone's website just to see if they carry the vacuum modulator (they don't but NAPA does) and I noticed that they actually sell transmissions, which I didn't know. They list a rebuilt C4 for like $600 and change, but $200 of it is a core charge so the final cost comes out to like $450ish. That is really surprising and makes me wonder why anybody would bother getting a C4 rebuilt by a transmission shop since it usually runs $1600 to rebuild a tranny. Plus, last time I bought a tranny from a junkyard it cost me $300 anyway, and that wasn't rebuilt. Jason
After re-reading this a couple of times I am wondering if you have any second at all. Are you sure it goes from low to second when you are in manual second? If the band or servo were bad you could get low in the 2nd gear manual position but the servo and band have to be working for it to go into second. it should NOT do that in manual 2nd. It should start out in second and stay there. I would bet that the 1-2 or 2-3 shift valves are stuck. Do you have the kick-down linkage on and adjusted? What speeds is it shifting at when it is in Drive, In manual second? What does it do in manual Low? Is it possible that you are getting 2nd and 3rd instead of 1st and 3rd in drive?
To summarize your post, I am pretty sure I am getting 1st and 3rd; not 2nd and 3rd. The reasons are as follows: 1) If I put it in drive the shift point is a little after 10mph.. which is where it would shift out of 1st normally. 2) If I put it in manual 2nd at a dead stop and take off, I have the same shift point at slightly past 10mph but much more acceleration and my RPMs are noticeably high above 30 mph, which would indicate 2nd gear. 3) On the highway, doing about 50, I went from drive to manual 2nd and the RPMs shot up noticeably which would be consistent with 2nd gear. I guess this doesn't have any bearing on whether I have 1st and 3rd or 2nd and 3rd though. I do have a kickdown linkage and it is adjusted to the point where if I pull the throttle level with my finger all the way back I can see the kickdown arm on the tranny moving. I can't tell, however, if it is engaging since it won't shift into 2nd gear while in drive. Jason
Why is this C4 shifting in manual second? It should stay in second as long as the lever is in second.
I may be mistaken but I believe that manual 2nd still allows the 1st to 2nd shift. Since, if you took off from a dead stop in 2nd it would likely stall. Jason
Nope that is a GM tranny. On a C4 Ford tranny if you put the select lever on "2" and take off from a dead stop it will take off in second gear and stay there until you either shift it our of "2" or blow something up. On a lot of the older "GM" trannies if you put the selector on "2" and take off from a dead stop it would take off in low or 1rst gear and then shift to 2 and stay in second. C4 doesn't work that way
Ah, my dodge truck shifts as well, so maybe it's just a Ford thing that it doesn't shift. I could've sworn that it shifted on the Comet when I had it in manual 2nd but I guess I will have to double check this weekend. Maybe it did shift and there is something whacky with the linkage. I also looked at the vacuum line going to the modulator, that looks ok but I didn't check vacuum on it, just eyeballed it. It looks like the crossmember has to be unbolted to change the modulator though, so that should be fun. Jason
I tried to do it without dropping the crossmember.. Not smart. Got a bath in ATF. Much smarter to support the trans, unbolt from the crossmember and drop it out of the way. Good Luck.
After taking the car out yesterday and playing with the transmission I think PaulS is right. I think I have 2nd and 3rd, not 1st and 3rd. Also, I verified that I was wrong about the transmission shifting in manual 2nd. When put in manual 2nd it stays in 2nd. So I'm thinking a stuck 1-to-2 shift valve? Do you think that the vacuum modulator can still be a culprit? I am going to pull the line off the back of it and see if there's any fluid. Jason
That means that the one way clutch is in backwards or is slipping. Time to tear the transmission down. The only thing that is removed after the one way clutch is the output shaft.
