transmission issue with fluid pressure?

[1968_Charger]

My car developed this issue where it takes some revving of the engine to get it to go into any forward gear. Reverse seems to work fine. Forward gears will jerk into place after I rev the engine up for a few seconds. Otherwise it acts like its in neutral. I know its not low on fluid and the clutches seem fine because once it does go into gear it drives normal. Shifting gears works fine. Its got a manual valve body as well. It just acts like it takes extra time or higher rpm for fluid pressure to build up in forward gears. Does that make sense to anybody? And if so what would cause that issue?

[fy469rtse]

John Kunkel will chip in, you have tried a band adjustment, drop the pan, see what colour your fluid is , dark  ? Sign that's slipping and toasting fluid,
Does it seem like its slipping at any time whilst driving it, could be so many things

[1968_Charger]

It doesnt slip at all once it goes into gear. Ive had slipping bands in a trans before and this is not the same. It literally feels like I have to rev the engine to get the pressure in the trans up enough for it to engage the forward gears. Reverse works fine and once I have gotten it to initially go into a forward gear shifting to other gears works fine as well as long as im driving it.  if I park it for a few minutes it will do the same thing again.

[Cooter]

Possible valve body trouble. Possible lip seals.

[fy469rtse]

There's plug in the trans that line pressure can be checked, but I keep thinking bad converter or pump

[John_Kunkel]

Does it do this only when cold after the first startup of the day or any time? If only after the first startup it's normal converter drainback, try starting in Neutral instead of Park.

If it does it all the time, the problem is pressure leakage in the rear clutch. It takes more pressure to apply a clutch than it does to keep it applied. If the pressure leakage is due to shrunken rubber seals, some "miracle in a bottle" like Trans-X or Lucas will often help.

[1968_Charger]

Yes it does it all the time. Ill try some of that seal stuff. See if that works.

[cudaken]

My car developed this issue where it takes some revving of the engine to get it to go into any forward gear. Reverse seems to work fine. Forward gears will jerk into place after I rev the engine up for a few seconds. Otherwise it acts like its in neutral. I know its not low on fluid and the clutches seem fine because once it does go into gear it drives normal. Shifting gears works fine. Its got a manual valve body as well. It just acts like it takes extra time or higher rpm for fluid pressure to build up in forward gears. Does that make sense to anybody? And if so what would cause that issue?

68 for the heck of it, had say a pint to quart of ATF. I had a trans dip stick shift a little. Showed as full but was low. What do you have to lose? 

OK, I see you are going to try a additive, I would use Lucas. Good stuff and stop the leak in my 727. That will also raise the fluid level.

Cuda Ken