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c4 trans slipping

Discussion in 'The Hokey Ass Message Board' started by leachafreak, Apr 14, 2013.

  1. leachafreak
    Joined: Aug 13, 2008
    Posts: 203

    leachafreak
    Member
    from dayton,oh

    got my pickup out today to take it for a drive. the truck drove fine til the motor got warmed then i noticed it was starting to slip a little like it was low on fluid. then it started acting like it was neutral so i pulled over and it would not go.i had someone pick me up and take me to get fluid. when i got back i checked the fluid (in park- motor warmed) thinking it was low and the fluid level is fine. so i put it in gear and it was fine. i started heading home and it would start slipping again at 10mph. my trans does have a pan leak so i don't understand how the fluid level is fine when i have trans fluid on my garage floor from it leaking over the winter. what steps can i take to try to figure out the slipping?
     
  2. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Very likely is ready for an overhaul. Any significant amount of slipping can wipe out the friction disc lining pretty quickly. And, something was already wrong for it to slip in the first place. My guess would be an "O" ring failure on a clutch pack piston, causing loss of pressure and resultant slippage.

    Do you hear any "whining" sound coming from the trans are? A pump failure will also cause slippage and they sometimes whine when failing. That can be diagnosed by putting gauges on the pressure port. Any tranny shop can do that for you.

    Ray
     
    Last edited: Apr 14, 2013
  3. You could try a band adjustment but if the fluid smells burnt it's probably to late.
    Loosen the jamb nuts on the adjusting screws and back them off a ways, tighten the adjusting screws to 10 lbs. ft. and back off 1 1/2 turns on the front and 3 turns on the rear.
     
  4. shinysideup
    Joined: Sep 1, 2008
    Posts: 1,627

    shinysideup
    BANNED
    from ruskin, fl

    It may need more fluid. Add a little and see.
     

  5. d2_willys
    Joined: Sep 8, 2007
    Posts: 4,285

    d2_willys
    Member
    from Kansas

    As mentioned, front pump and/or forward clutch piston o-ring seal. These transmissions are really pretty simple to rebuild, and parts are cheap.
     
  6. leachafreak
    Joined: Aug 13, 2008
    Posts: 203

    leachafreak
    Member
    from dayton,oh

    no whining sounds at all... just slips like its low on fluid.
     
  7. leachafreak
    Joined: Aug 13, 2008
    Posts: 203

    leachafreak
    Member
    from dayton,oh

    the fluid smells fine and looks good. that was going to be my next step. im going to drain the pan, put a new filter in it, adjust the bands, and put in 3 to 3.5 quarts of fluid. because it acts like its low but the dip stick says its fine, but i dont know if the dip stick is a cheep aftermarket and its just reading full when its not.
     
  8. leachafreak
    Joined: Aug 13, 2008
    Posts: 203

    leachafreak
    Member
    from dayton,oh

    thats what i think but the dipstick says its full.
     
  9. leachafreak
    Joined: Aug 13, 2008
    Posts: 203

    leachafreak
    Member
    from dayton,oh

    thats good to know.
     
  10. leachafreak
    Joined: Aug 13, 2008
    Posts: 203

    leachafreak
    Member
    from dayton,oh

    would it hurt the trans if i put a half quart of fluid in it to see what it would do? or better off draining fluid and putting 3 to 3.5 quarts in it so i dont over fill it?
     
  11. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Running it a little overfull won't hurt anything as a trial. Longer term usage overfull can cause fluid foaming and is not a good thing.


    Ray
     
  12. leachafreak
    Joined: Aug 13, 2008
    Posts: 203

    leachafreak
    Member
    from dayton,oh

    thanks guys for all of your help.
     
  13. leachafreak
    Joined: Aug 13, 2008
    Posts: 203

    leachafreak
    Member
    from dayton,oh

    I checked my fluid level this morning when truck was cold and it read full. Does the fluid level read the same when the car is hot or cald?
     
  14. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL


    Not usually. Cold is usually a bit lower on the dip stick....higher when warm due to the natural expansion of the fluid from heat. Most automatics are to be checked when running so the pump fills the converter and the level shown is in it's operating condition. A converter will sometimes drain fluid back into the case when not running. Isn't supposed to, but sometimes does.

    Ray
     
  15. castirondude
    Joined: Jan 26, 2012
    Posts: 496

    castirondude
    Member

    What can you tell us about the history of the pickup, how long have you owned it etc?
    O-rings were mentioned, that's a definite possibility , but usually happens after sitting a long time. Ditto with torque converter draining, usually happens on transmissions that were not used for a few years at some point in their life. The symptom of bad orings is that the transmission intermittently will "miss" certain gears (go to neutral). If you rev the engine high it will slam into gear and once in, it will hold good even at full throttle. If the clutches are worn out it will behave consistent and slip at heavy throttle

    Sent from my Verizon 4G LTE smartphone
     
  16. leachafreak
    Joined: Aug 13, 2008
    Posts: 203

    leachafreak
    Member
    from dayton,oh

    So i adjusted the bands rechecked the fluid level. I took it for a drive and it is shifting fine... so far. But now i noticed when i am coming to a stop i can slightly feel the trans down shift. Is this normal? I am used to 350th so i am not sure if thats normal on a c4.
     
  17. leachafreak
    Joined: Aug 13, 2008
    Posts: 203

    leachafreak
    Member
    from dayton,oh

    I have owned the truck for a year. It has always drove and shifted fine. It does leak a little trans fluid. But fluid levels are fine everytime i chech which i dont get. The only time it sits is for the winter. The truck does not miss any gears but it did act like it was going into nuetral. I never reved it high to see if it would slam into gear i would let off the gas and feather it again and it would go for a minute then act like it was in nuetral again. But i adjusted bands today and it did fine. Accept i felt it slightly down shift when i would come to a stop.
     
  18. castirondude
    Joined: Jan 26, 2012
    Posts: 496

    castirondude
    Member

    Hmmm I suppose if turning the truck off for a few minutes helped, that could indicate a filter problem. I've had that a lot with fuel filters. Made it home more than once just stopping every 10 miles LOL. Shut it off for a minute and drive another 10 miles till the fuel pressure drops again.
    But that being said I have never heard of transmissions having a clogged filter, they are usually surgically clean inside. Plus the old transmissions just have a pickup screen so not much to clog up there.

    Sent from my Verizon 4G LTE smartphone
     
  19. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    I respectfully disagree that worn/leaking "O" rings are primarily found in vehicles that have sat, unused, for long periods. I DON'T disagree that that CAN and does happen, only that it isn't the ONLY most likely cause. After all, the piston in the clutch pack is moving a lot, every time the clutch pack is applied or released, there is some movement of the piston and potential wear to the "O" ring seal.

    I had this very condition many years ago with a C4 in and nice little '65 Falcon. Went thru the tranny and replaced seals, "O" rings, clutch plates, bands and it worked great after being freshened up.

    If you don't have much to lose by trying it for a few days, drive it and see what happens. Worst case, you pull it and rebuild itr or replace it with another. As was pointed out in an earlier post, they are simple as automatics go.

    Ray
     
  20. castirondude
    Joined: Jan 26, 2012
    Posts: 496

    castirondude
    Member

    FWIW Band adjustments are rare. Never owned a c4 but lots of c6. The c6 has a band adjustment and at most it needs to be adjusted once in the life of the transmission, but usually not at all. I have 170k miles on my transmission since it was rebuilt 13 years ago and never adjusted it, still shifts fine. Just change the oil every 50k miles (I always drain the torque converter as well)

    Sent from my Verizon 4G LTE smartphone
     
  21. Diavolo
    Joined: Apr 1, 2009
    Posts: 824

    Diavolo
    Member

    I have to ask, because everyone is assuming you are doing it right but...

    You are checking your fluid level with the trans warmed up, running and in gear? If you aren't doing all 3, you won't get the correct reading.
     
  22. leachafreak
    Joined: Aug 13, 2008
    Posts: 203

    leachafreak
    Member
    from dayton,oh

    And the trans fluid looks like new on the dip stick
     
  23. leachafreak
    Joined: Aug 13, 2008
    Posts: 203

    leachafreak
    Member
    from dayton,oh


    Thats exactly what im gona do
     
  24. leachafreak
    Joined: Aug 13, 2008
    Posts: 203

    leachafreak
    Member
    from dayton,oh


    I checked fluid warmed up, running in park. Sould it be running in drive?
     
  25. castirondude
    Joined: Jan 26, 2012
    Posts: 496

    castirondude
    Member

    I have read that before as well, I tried it both ways and it didn't seem to made that much of a difference. I did find it helps when you remove the dipstick, wait for an actual minute before putting it back in, otherwise it will have oil all over it. Also read both sides of the dipstick.

    I had a 68 lincoln before that sat for 20 years before I bought it. It had similar problems, sometimes it would not go in reverse. Put it in neutral, rev up to 1500 rpm then put it in reverse, it would go. I drove it for 5 years. Sometimes it seemed like it was getting better and then sometimes it came up again. I think a rebuild is the only real cure. If you can do it yourself I think it is only 300 dollars orso

    Sent from my Verizon 4G LTE smartphone
     
  26. leachafreak
    Joined: Aug 13, 2008
    Posts: 203

    leachafreak
    Member
    from dayton,oh

    Thanks everyone for all the great info. I guess all i can do is is see how it run for the next couple weaks and if it still acts up i will get it rebuilt.
     
  27. castirondude
    Joined: Jan 26, 2012
    Posts: 496

    castirondude
    Member

    Have you made any new findings?

    Sent from my Verizon 4G LTE smartphone
     
  28. DetroitRefugee
    Joined: Apr 2, 2013
    Posts: 3

    DetroitRefugee
    Member
    from Middle TN

  29. Pops1532
    Joined: Jun 19, 2011
    Posts: 544

    Pops1532
    Member
    from Illinois

    I've had several C4's. Every one had "check while hot idling in park" stamped on the dipstick.
     

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