74 ford tranny

[molinebob]

I have a 1974 Ford F250 4x4 with a snow plow on it, put the plow on last year, has a 360 with the C6 trans, question is sometimes it goes in gear right away others i have to rev it way up then it goes, and after act like nothing ever was wrong, going down the highway it works and shift as it should, if i run it for along time it works without problems, unless i let it idle for a long period of time in park then it acts up for the first time going into forward, no probs with reverse at all, just forward, if I manually shift it to low and up it still does it....replaced the fluid and filter and still does it...fluid was not burnt at all..has me stumped as to what could be wrong with it...Thanks for any and all help..Bob
 

[oldtanker]

Pull the vac line off the modulator and check for tranny fluid in the vac line. If it's there replace the mod. Other than that You may have a problem with the vlave boby.

Rick
 

[Dick W.]

Try 1 quart over the full line. A lot of C6 trans do better with the extra quart. What oil did you refill it with? Is the kick down rod connected and operating properly? Its been too long to remember how that all works without seeing one! Does it have a vacuum modulator on the right rear corner? Are the cooler lines kinked too tight too allow good oil flow? Enjoy your old Ford, we updated last year after rust ate our 85 F-250 4x4.
 

[notjustair]

Not familiar with that trans, but with others that can be because it isn't building enough pressure to shift. Could be internal seals going.

I had one doing that and put Lucas for transmissions in it and it turned it right around. Made that trans work for many more miles. It won't fix it, but if you need 5000 miles out of it you might be in luck.
 

[ericlb]

like others said what kind of fluid did you put in it, i believe 74 still used type F fluid, but you need to check that also the linkage, if sloppy [ bushings worn on the linkage rods], occasionally it may not be going all the way into D but hanging up a little in nutural
 

[504]

Check the front cab mounts just about where your feet would be. The stamped steel cab frame will rust out and let the cab drop just enough for it to set on the steering column, when that happens, it really can mess with the column shifter. And yes, Type F fluid only
 

[davpal]

I had one that did that and the guy I had rebuild it said it had bad piston rings on the pump letting the pressure escape. It would only do it when I backed out of the driveway and put it in drive, it would hesitate before going which I found to be very irritating and dangerous. In other words you have an internal leak and it needs a rebuild kit installed.
 

[Allan in NE]

Those C6s are bad about that.

Since you have to pull the transmission out to replace the torque converter anyway, might as well go ahead and overhaul the beast while it's out.

Allan
 

[ASEguy]

You don't have problems in reverse because the high reverse clutch is't involved. If no problem in second the kickdown band is good enough too. Sounds like your problem is the forward clutch assembly seals. When they are cold they shrink and allow for pressure loss. When they warm a bit they swell and seal better which is why it's ok after start-up.
Gerard
 

[VernMI]

Teflon seal rings have trouble energizing when cold. They rely on pressure behind them to push them out against the seal surface and in your case the oil flow is going around them until there is enough flow to build pressure to push them out against the seal surface. Higher engine speed increases the oil flow until they finally energize. Teflon seal rings have very little "memory" so they don't spring into place like a cast iron ring. Some seal rings are solid one piece while others have "scarf cut" ends. New seal rings will probably fix the problem because they are slightly more pliable and don't have the wear that is on the old rings.