HELP !!! I'V GOT A 77 WITH A 3 SPEED AUTO. IT IS SLIPPING OUT OF DRIVE, IT WILL STAY IN 1ST OR 2ND BUT SLIPS OUT OD 3RD WHEN IT GETS HOT. ANY HELP WILL BE GREAT. THANKS RJ

Just when hot or all the time? In my 1962 Falcon my C-4 did that then totaly stopped working(hot or cold),(I put in a 1967 289 C-4 combo in it if you were wondering). I still had 1st, 2cnd and reverse but no 3rd. I went thru 4 trannys that way(I kept buying junkyard trannys). Now I am going to swap a 4spd manual into and solve all my problems(and to create new ones LOL). From what Iv'e been told was that as the 2cd to 3rd clutces wear out the springs in that clutch pak can only reach so far, once that starts hapening it usualy goes downhill form there(and fast). Thats why when you get it rebuilt they(tranny shop) put in more springs and clutches into that clutch pak to make it last longer and to give you a firmer 2cnd to 3rd shift, it also holds stronger. Hope this info helps. Also somthing else to consider, have you checked your linkage to make sure that it is adjusted correctly?

it slips when it warms up, get worse as it gets warmer...........will a filter cause this?

Not that I'm aware of but a fresh one couldn't hurt(at least worth a try). If you do pull the pan check for chunks, a little glitter on the bottom is normal. If it gets worse as it gets warmer than my thought is that the piston that pushes on the 2 to 3 shift is losing is seal(it usally has two o-rings on it), they might be worn enough to work when cold but not when warm or hot. the reason is that cold fluid is stiffer(or thicker) and wont pass by the seal as much but when the fluid gets warmer it thins out a little bit causing it to leak past the o-ring seals , ie; a very loose and slipping shift(if it does shift). If the o-rings are what you find to be bad you could just have them replaced but it is only a band-aid fix. the rest of the tranny is probably not far behind.

you'v been a great help thanks

I just swapped my C-4 for a 4spd Toploader, and I am usually still in 3rd gear by the time I hit 100mph. I also have a H.O. 351 Windsor, so it really helps with the take-off. Good luck

What kind of gearing are you using? May have to change to gearing a little higher to get the top end you want...