C4 Tranny issue..

Discussion in 'Technical' started by Chief1010, Apr 14, 2017.

  1. Chief1010

    Chief1010 Member

    Joined:
    Apr 27, 2014
    Messages:
    89
    Likes Received:
    7
    Trophy Points:
    38
    Location:
    Kentucky
    Vehicle:
    72 Maverick 306, 351W heads.. 75 Maverick ( parts car )... 71 Maverick ( in storage ).. 71 Torino 500 ,306, TCI Trans, Detroit Locker..
    I have a older TCI C4 transmission ( about 6 years old ) in my 71 Maverick.. I've never had a issue with it until a couple of weeks ago.. Had a line to leak ( easy fix ). About a week after I fixed the line I noticed the tranny would delay shifting into 3rd ( only when cold ). Over the last week or so it has gotten worse to wear it doesn't want to shift into drive at all ( cold or hot ).. When I replaced the fluid after the leak I used Lucas synthetic fluid.. If somebody thinks the modulator could be going bad does anybody know if it would be the screw in or push in.. The transmission was originally bought for a 71 Torino.. Any info would be greatly appreciated..
     
  2. 71gold

    71gold Frank Cooper Supporting Member

    Joined:
    Apr 9, 2002
    Messages:
    25,773
    Likes Received:
    2,400
    Trophy Points:
    828
    Garage:
    1
    Location:
    MACON,GA.
    Vehicle:
    '73 Grabber
    was the...Lucas synthetic fluid...for a TCI C-4?
     
  3. Krazy Comet

    Krazy Comet Tom Supporting Member

    Joined:
    Sep 13, 2012
    Messages:
    6,989
    Likes Received:
    1,829
    Trophy Points:
    521
    Garage:
    1
    Location:
    Chesapeake VA
    Vehicle:
    1972 Comet GT clone 306 . 1969 Fairlane Cobra 428CJ 1988 T-Bird awaiting 331 ..
    Modulator valves can cause no/late shifts but generally would also have issues with 1st to 2nd as well... I have seen a pinched vac line to modulator that caused early 1st - 2nd shift and very late 2nd to 3rd shift...
     
  4. Chief1010

    Chief1010 Member

    Joined:
    Apr 27, 2014
    Messages:
    89
    Likes Received:
    7
    Trophy Points:
    38
    Location:
    Kentucky
    Vehicle:
    72 Maverick 306, 351W heads.. 75 Maverick ( parts car )... 71 Maverick ( in storage ).. 71 Torino 500 ,306, TCI Trans, Detroit Locker..
    The Lucas synthetic fluid said it was for most cars.. Specifically Ford, Dodge, and Chevrolet.. And it shifts out of 1st rather quickly because it has 3:70 gears.. I guess my vacuum port in the intake could be partially clogged.. Never thought of that... Thanks for the info guy's
     
  5. mrmalina99

    mrmalina99 Member

    Joined:
    Oct 20, 2010
    Messages:
    752
    Likes Received:
    23
    Trophy Points:
    76
    Location:
    Warner Robins, GA
    Vehicle:
    1973 Maverick
    I thought these transmissions had to have Type F due to friction requirements.
     
  6. 71gold

    71gold Frank Cooper Supporting Member

    Joined:
    Apr 9, 2002
    Messages:
    25,773
    Likes Received:
    2,400
    Trophy Points:
    828
    Garage:
    1
    Location:
    MACON,GA.
    Vehicle:
    '73 Grabber

    when stock...rebuilds use different materials...:yup:
     
  7. mrmalina99

    mrmalina99 Member

    Joined:
    Oct 20, 2010
    Messages:
    752
    Likes Received:
    23
    Trophy Points:
    76
    Location:
    Warner Robins, GA
    Vehicle:
    1973 Maverick
    Good to know, I was not aware.
     
  8. groberts101

    groberts101 Member

    Joined:
    Apr 22, 2007
    Messages:
    4,166
    Likes Received:
    533
    Trophy Points:
    282
    Garage:
    1
    Location:
    Minneapolis, MN
    Vehicle:
    1971 Comet GT
    yeah.. back when they were stock. Move away from that with aftermarket clutches and tighten up the tolerances?.. all bets are off. Friction modifier packages and viscosity changes between various brands imposes far more effect on torque capacity and line pressure.
     
  9. Chief1010

    Chief1010 Member

    Joined:
    Apr 27, 2014
    Messages:
    89
    Likes Received:
    7
    Trophy Points:
    38
    Location:
    Kentucky
    Vehicle:
    72 Maverick 306, 351W heads.. 75 Maverick ( parts car )... 71 Maverick ( in storage ).. 71 Torino 500 ,306, TCI Trans, Detroit Locker..
    I talked to TCI about the issue.. according to them it could be one of a few different things.. Vacuum line plugged ( checked it's fine ), modulator valve may come loose or is bad, or my lease favorite scenario is that there is a internal issue.. I ordered a new modulator valve and pray that is the issue. But since I know what kind of luck I have. I will probably be pulling the transmission.. Yea me..
     
  10. baddad457

    baddad457 Member

    Joined:
    Feb 24, 2007
    Messages:
    5,861
    Likes Received:
    140
    Trophy Points:
    171
    Location:
    Opelousas La.
    I was thinking the same thing, it's never a good idea to switch fluids like this either.
     
  11. 71gold

    71gold Frank Cooper Supporting Member

    Joined:
    Apr 9, 2002
    Messages:
    25,773
    Likes Received:
    2,400
    Trophy Points:
    828
    Garage:
    1
    Location:
    MACON,GA.
    Vehicle:
    '73 Grabber
    I've heard of people changing the same brand/type fluid in a high mileage transmission and it not even pulling off the rack when done.
     
  12. Krazy Comet

    Krazy Comet Tom Supporting Member

    Joined:
    Sep 13, 2012
    Messages:
    6,989
    Likes Received:
    1,829
    Trophy Points:
    521
    Garage:
    1
    Location:
    Chesapeake VA
    Vehicle:
    1972 Comet GT clone 306 . 1969 Fairlane Cobra 428CJ 1988 T-Bird awaiting 331 ..
    Old wives tail... I don't believe it could happen, not even for a second... No doubt performance/longevity could be effected on trans that uses exotic fluids...

    I've switched between F, Mercon and Mercon III in sever different Ford transmissions without issue... Of course these were stock trans...

    I ran nothing but F in the AOD that I raced in T-Bird for nine years, that trans is still good...

    Ran a slipping AODE from 33K to 131K on F before the front pump to case gasket finally started leaking... Also put F in a 140K-ish A4LD that kept locking up after coming to a stop, worked fine afterward...
     
  13. groberts101

    groberts101 Member

    Joined:
    Apr 22, 2007
    Messages:
    4,166
    Likes Received:
    533
    Trophy Points:
    282
    Garage:
    1
    Location:
    Minneapolis, MN
    Vehicle:
    1971 Comet GT
    If you mean freshening used fluid for same exact new fluid?.. then I would imagine the trans was already close to failure mode with excessive clearances and pump wear. Wouldn't a cold vs hot line pressure test have clarified a preexisting condition? Through the years I've heard this caused issues for several people. Nothing quite that extreme though.

    Have also burned up a trans that was already marginally worn by changing the clutch lining debri'd oem fluid over to full synthetic. Wife burned it up on the way to work in less than 2 weeks. She quickly blamed me for recently changing the fluid.. said I should have left it alone. I never came completely clean about swapping over to full synthetic though. She's smart enough about all this stuff it would have surely raised another red flag. lol

    I've talked with many about the negative effects of freshening fluid on an already worn out unit and the only logical explanation I've ever heard came from an old retired Ford tech. He basically said to imagine the debri in the fluid acts like another form of friction modifier. I remember countering with the question of "but what about the increased frictional wear and debri accumulation in the valve body"?.. that would surely come from running the same dirty fluid. He said something to the effect of.. "are you more worried about increased clutch wear rates and higher possibility of stuck valves?.. or completely wiping out the frictions altogether due to the increased slipperiness of the new fluid?"

    The first 2 possibilities are stressful "what if's" that keep you babying the trans for many more miles down the road while the 3rd leaves you with false sense of security(because everybody knows fresh fluid is like a trans tuneup in a bottle, right?) until you suddenly drive the clutches right into the pan.
     
    Last edited: Apr 18, 2017
  14. Krazy Comet

    Krazy Comet Tom Supporting Member

    Joined:
    Sep 13, 2012
    Messages:
    6,989
    Likes Received:
    1,829
    Trophy Points:
    521
    Garage:
    1
    Location:
    Chesapeake VA
    Vehicle:
    1972 Comet GT clone 306 . 1969 Fairlane Cobra 428CJ 1988 T-Bird awaiting 331 ..
    New fluid has fresh friction modifier so would no doubt give a softer engagement, possibly speeding failure of a trans that was on already on it's deathbed... If the old fluid has so much debris as to be benefiting clutch engagement I can't see the valve body even beginning to operate properly...

    That was issue on the A4LD I mentioned, debris in the pan... That one had been cleaned and serviced with Mercon at least twice before I douched it with F... For that service I removed cooler line and dumped in the new F while old fluid was pumped into bucket(nope I didn't remove pan)... Both previous times also stopped the lock up after a stop...

    F will give slightly crisper shifts, the GM guys used it for years in their TH 350 & 400, to firm the shifts...
     
  15. groberts101

    groberts101 Member

    Joined:
    Apr 22, 2007
    Messages:
    4,166
    Likes Received:
    533
    Trophy Points:
    282
    Garage:
    1
    Location:
    Minneapolis, MN
    Vehicle:
    1971 Comet GT
    Tom, while I could easily agree with most of that, you probably know just as well as I do that there are many cars running around with filthy fluids in the pan. People seemingly think it's a lifetime fluid or just too damned cheap and ignorant to really care. I know because I've bought more than a few like that through the years. Upon fluid/maintenance inspection you know things might get ugly.. but the deal is too good to pass up. Not all of them work out, especially the ones that seem too good to be true. Wow!.. new paint?.. I'll take it at full price! lol

    The main reason I gave more credence to that old mechanics input is that if you rub fairly dirty and/or burnt fluid between your fingers?.. it has sandpaper like grit that easily makes its way past those miserably large meshed filters. But yeah, I have been amazed at the amount of lining/steel sludge that can build up in the bottom of the pan and free flowing fines that keep running through all the various circuits without causing complete failures. Seems to me that letting cars maintained like that sit for too long does far more to cause sticky or stuck valves than just the free flowing fine sandlike silt ever does on its own when the car is still operational. Settles and solidifies in the VB after long no-run storage and things go south fast. Same goes for oil and fuel too.. not running them often enough to keep the juices flowing and water burned off is bad for long term durability.
     

Share This Page