How to Test for Transmission Problems

[justin1987]

Do any of you all have any tips or tricks to test a transmission to see if it is going out?

When we restored the Charger 9 years ago we pulled the 727 transmission and the 440 out of a 1967 Chrysler New Yorker and went through the entire engine, but just did minimal stuff to the transmission (i.e. gaskets, etc.). It always seemed a little weak, but it seems worse now. When I start the car up and put it in drive or reverse I have to give it a lot of gas for it to start moving. Once it is going it seems fine. It just doesn't much acceleration from a stop. The people I have talked with (not professional mechanics) have mixed views on what is causing the problem. I think it's time to rip the transmission out and put a new one in. Thoughts?

[71 SE3834V]

Upon starting try putting it in neutral for 15-20 seconds before putting in drive. Sounds like the torque convertor is draining down while sitting.  Kinda common. It'll fill up faster in neutral. If you try to drive right away you're slipping the clutches.
Does it seem normal after a short time? If not then sounds like it's slipping all the time.
I'm sure John will pipe in here with better advice.