Okay guys I need a little input...my C4 is slipping from 2nd to 3rd...the rpms jump way up and then it jams into gear. I have heard you can tighten the band in the C4 from the outside but I don't know how to do this. Does any one have any advie or direction ? Thanks !!
Maybe I can shed some light on this, first to adjust the bands, there are two adjustments. One on the front drivers side of the trans and one on the passenger side at the rear where the cooler lines are. The rear one is for low and reverse only, the front one for second gear, loosen the lock nut and back it off several turns on the stud. Using a very short wrench, turn the stud in until you just feel pressure against it, you are tightening the band against the drum. Now back the stud off exactly one and a half turns(some call for one and three quarters but I use a little tighter setting) then while holding stud in that position, tighten the lock nut. Same procedure can be used for rear one, I still use the 1 1/2 turns for it too. seems to work fine for me. Your symptoms sound like either of three things 1. Loose or worn out front band. 2. Worn foward clutches or 3. Worn or leaking servo(pushes the band tight on the drum). There are some other little things that could affect it also like low fluid, dirty or leaking valve body or modulator. I would suggest dropping the pan and changeing the fluid and filter, if you find large deposits of black "mud" in the pan then clutches are probably going away among other things. If the clutches are worn it makes a lot more clearance in the clutch drum and the piston has to push all this farther foward to lock up, this would cause that long delay in between shift points. The C4 is one tuff little trans for it's size but high mileage and lack of maintenance such as fluid changes will take a toll on them or any other automatic transmission for that matter. Hope this helps a little.
Thanks a lot..it helped more than a little. Now that finals are over I should have time to drop the tranny and change the fluid. I wa also thinking of adding an external filter. Have any suggestions as to which to use? Thanks again.
C4 Don't think you need one, but it's your choice on that, if you don't have one yet, invest in a good trans cooler ie, Hayden or the like. Heat is one of the most damaging elements to an automatic, with the mods you have made to your HP output, you will need the cooler. Some new vehicles come with them now besides the radiator cooler. Another tip you may want to try is find a servo that has the letter H stamped on it, yours is probably a B or A. The H model has a larger piston diameter and will clamp the band with more force, have found these in C4's lying in scrap yards waiting for aluminum prices to go up. eBay sometimes has some but are going for high dollars. They bolt right in with no problems but must have pan off in most cases to line up the struts that it fits in etc. A good quality Type F fluid is another benefit, the Wal- Mart stuff works for everyday puttzing along but for some serious foot mashing on the accellerator, I would use Amaco or another well known brand. The auto trans is nothing but a hydraulic pump that routes fluid into chambers to activate various gears etc. I am no expert on them but have blown enough of them up in my day to find out some ways to make them live longer. First one I attemted to repair was a 64 Olds "Slim Jim" hydramatic. There was one big and complicated tranny, local library manuals and some cussing resulted in a nice overhaul job. The C4 is a piece of cake to most, ie C6. TH400 etc. Don't even want to attempt the front wheel drive ones, to damn old to mess with that configuration. Good luck as always.
along those lines, my c4 sometimes has a hard time making up its mind on what gear to use.. 48k on it. not losing fluid. it goes from 1st to 3rd. if i give it enough gas it'll go to 2nd then 3rd at the right time. recent trans service... 5k ago. shifting smooth ..then sometimes it runs as it should. any ideas? thanks
C4 Sounds a little like a vacumm problem to the modulator. Could also be a stickiing 1 to 2 valve in the body, and it may be a sticky governor. I would check rubber hoses first, pull the one off the modulator and see if any fluid runs out, indicating a bad modulator itself. One other thing you may try(but don't overdue it) is to manually put the trans in 1st and floor it till you reach a peak rpm then shift to 2nd and wind it up again then 3rd. This will sometimes break loose any sticking valves and especially the governor, please do this in safe place and don't punish the engine to hard. 5000rpm or so, One micro size piece of trash in the works can cause havoc with close fitting valves etc. Make sure your selector rod and such is not worn and the bushing in the lever on trans itself, causing a mis aligned gear selection. Leaking seals and a host of other little gremlins could be the culprit but I lean towards a vacumm problem right now. If all else fails have someone put a pressure gauge in the port on the side of the trans and see if the hydraulic pressure in each gear is where it's supposed to be. These numbers are listed in any good trans manual for C4's. I have found that the big snafu in these trannys is a leaking valve body , either overtightened mounting bolts or in some cases a bad seperator plate gasket. Most people just drain the trans fluid and either clean or replace the filter when servicing the trans itself(am as guilty as the next on this one) but if the lines and radiator cooler are not flushed out too then any dirt and such will go right back into the fresh oil. The filter will stop most of it though, some convertors have a drain plug and most don't. The filter itself can be washed out and reused but if you look clear back under the metal cover, nine times out of ten it's packed with trash even though the visable screen is clean. Just a few ideas for you to work on. If all else fails take it to a qualified trans person and they probably have more knowledge on this stuff than this part time mechaneck.
now mine is doing almost the same thing,it was working fine till I paid 61.00 to have the fluid and filter changed,now it fills like it shifts in to nuetral for a second before going into third,it doesn't slam into third,it almost fills like its slipping. A friend of mine told me that they left out a small spring and plug that is on top of the filter and that i am fixing to burn up my tranny.It's raining here and about 41f with possible sleet tonight but after work I guess I will be out in the carport pulling the pan. Does anyone know if the plug is tappered or if it matters which way it goes in? It has something to do with high pressure to the high gear clutches.
I changed my filter once, and i lost the spring that you refer to that is held between the filter and a small valve in the valve body. This WILL cause your tranny to turn crappy. It will take like 3 seconds between gear changes allowing the engine to wind into some retarded RPMs. I would suggest taking a look into this because if you dont, yes you could be looking for trouble in the near future.
On first starts in the morning or when it's cold I shift into reverse no problem. Then I shift it into drive and it doesn't go in. It used to take a few seconds now it seems to be getting worse. I can pull it down into 1st and it engages just fine and after that I can put it into drive and it works just fine. What's my problem? I put new fuild and filter in it about 3 thousand miles ago.
I finally got under mine Sat. night and pulled the pan & filter, sure enough the plug was missing,the spring was there but no plug.My neighbor is a 5.0 mustang nut( has 3 in his drive plus an 84 ford 150 that he put a 5.0 with fuel Injection in) had the plug that I needed so I put it all back together. The transmission shop also told me that they had put dexiron fluid in it ,that what they put in all Fords,said it had more lubercants in it and would make it shift softer,thats why Ford switched to it( I thought that was probadly why it was shifting like that) My neighbor kept telling me it was that plug & spring( really called a high pressure valve not a plug) I only drove it about 2 days before I parked it till I could cheak it. Anyway,I put type F fluid back in and it works great! Anybody thinking of a filter change watch for that spring and valve! The filter is what holds it in and it WILL fall out when you pull the filter! I also learned that type F in later AOD automatics will make them shift a lot firmer. I know all you guys were worried about me so the good news is: me & the grabber are back terrorizing Azle,Texas!
C4 Very good job of fixing it, I think I would maybe have a talk with that shop about their screw up. Might could get the cost of the new fluid and valve out of them. Had a bit of fun with the local newbie clerk at the AZ store. Plunked down 8qts of type F fluid on the counter, in a very friendly and helpful way, he asked me what kind of car that I was going to use it in. Devilishly, I said "72 Chevrolet" he almost got down right uppity about it. " You can't use type F in a GM trans, you'll burn it up. I replied "been using it for 40yrs and never had one burn up yet, makes-um shift harder, thats why I have had this sore neck for a long time now. Needless to say not another word was uttered and I exited with a slight grin on my lips. Always run F in powerglides for racing, Ford has switched to a Dexatron fluid in the later models for us old guys to drive in comfort etc. If anyone is still leary about using it, just add a little Lucas trans additive and you'll have both types covered as far as lube quality goes.
Megawes, Usually the *reverse first, then delay into drive* scenario is an indicator of low pump pressure or restricted flow to the pump. Since I am assuming you change your filter and fluid regularily, I suspect that you are about due for a soft parts overhaul.
ive had the same problems with my c-4 after a complete rebuild.had it in and out 3 times.the trans guy couldnt find anything so now ive got a new one well another rebuilt one i hope it works ok.nice thing is whatever needs to be done to get the othe trans right i dont have to pay for nice to have a guy with a garentee even if it is a race car.things to check (servo,modulator,valvebody,bands,and cracked trans case,) just some thought and dont feel alone theres alott of c-4s out there thats have flaring problems when shifting from 2nd to 3rd. good luck to all i know how you feel.
