noticed this more when car is cold (before first drive). 77 280,5 speed, mostly stock that I know of. worst when temp is COLD outside, you can push in the clutch, start the car, put tranny in nuetral and let out the clutch and 2 things happen. #1 as you let out the clutch the engine rpms will drop 200 or 300 rpms like there is a load on engine and #2 if you dont have the brake on the car will actual try to creep forward with the clutch disengaged and the tranny in nuetral. I do think that the tranny was filled or at tleast ALOT of LUCAS GEAR OIL used in it not positive thou!

Any Speculations????

In cold weather your tranny fluid becomes almost solid. When you let the clutch out, it turns the input shaft in the transmission and slows the engine down. It will also start to move the gears in the transmission hydraulically. I had a BMW 3.0 in St. Louis and the only way I could start the car was in neutral with the clutch IN. It would die when I let the clutch out in NEUTRAL. I had to warm everything up before I tried to put it in gear. I changed to synthetic tranny fluid and it stopped doing this. 90# oil at 20 degrees is very difficult to stir! I would try putting synthetic oil in your tranny. I think this will solve your problem. Let us know!

I couldnt agree more with Zsaint well said and answered post.

thanks guys, good inexpensive starting point!