Transmission Fluid Level

74 Southwind 351 Velvet Drive. 2 weeks ago after a while the trans slipped just a bit, so stopped & added fluid to top notch of dipstick. Ran fine for another hour...stopped for day, checked dipstick & fluid still full. (was with Morfoot that day)

Last week, checked fluid prior to start and was down a bit below half on stick. Added fluid to full notch, ran great 4+ hours, when stopped fluid still full.

Tomorrow, I'd guess it's going to be halfway down again. Question is:

1) is this due to fluid temperature expansion/contraction or might I have a leak?

2) fluid should be checked hot, but I normally prefer to check oil & tran fluid before setting off. What notch level should fluid be when cold?

3) Also, what is total quart capacity of circa 1974 velvet drive, and how also what is quantity that is evident on the stick; i.e. from full top notch to no fluid showing what might be the volume amount?

If you are loosing fluid but you don't see any external leaks, then it's your cooler. You can pull it off and run a pressure check on it. Hook regulated air up to the oil side and stick the cooler in a bucket of water.