Building A C4

Discussion in 'Classic Mustang Specific Tech' started by John Grunwald, Jul 27, 2013.

  1. So after my first trip to the track I blew up my c4 :)
    Ive been having chronic problems with it since we hooked the 331 up too it, its a stock tranny with a shift kit and 3200 stall converter
    The engine is making over 400 hp and whenever I run it hard for a little the trans starts blowing oil through vent and dipstick.
    I ran it down the track twice and it was fine. It wasn't till the 3rd run. When it shifted 2-3 it started slipping and trans oil sprayed out. Now it has no 3rd and I have a problem going into reverse.
    it shifts " Ok" into 1-2 but when it goes up to 3rd it just free revs.

    Now I understand that there are a million things that could of went wrong but does anyone know of a good overhaul kit to go with? And whats the differences with all the kits? I wanna do a complete refresh but change out key components so it doesn't fail again. Ive done some research on it and looked into forward clutches etc...
    Im going off to college soon so this is most likely going to be a budget build on the tranny.
    What is really necessary for a 450+ hp build?
    Hardened input shaft? Clutches? Performance Auto has a kit for like 250$ but is that going to have all the stuff I need?
    I should be picking the car up from my dads shop in the next couple of days.. Crossing my fingers that there is no metal in the pan!
  2. Start with tearing it down, and making sure there are no other damaged hard parts. A good kit like this would be the way to go, with a deep pan, and a new trans cooler. The burnt clutch material is difficult to get out of the cooler. Sounds like it was under cooled any way. The high-reverse clutch pack controls third and reverse.
  3. Will that kit be good enough? And does it have all the stuff I need? Also what about reverse clutches?
  4. Your 3rd gear clutches were either on their way out or your line pressure was low. When it was puking fluid it was likely too hot which contributed too. Any of the three could have started it all.

    The same clutch pack that controls 3rd also is used for reverse. I like this one. It has an extra clutch in the pack you likely burned up. Jay at Broader Performance can tell you what line pressure should be at the level you are talking about. I would start with a 70+ C4 or even better would be a C5. I would at least use a 70+ forward drum. Do you know what spline input shaft you have?
  5. It's actually out of a 76 maverick
  6. That is good. There are a couple oiling mods to make on the case and planetaries. Google c4 monster thread. There is a lot of diy help.
    daveinmontrose likes this.
  7. Check out Broader Performance (good guys - they get a lot of positive feedback on net) - they have a rebuild kit that should stand up to what you are running. Summit also sells a c4 with shift rated to 450 for under a grand,