I have a 90, 305 powered formula. the problem is while driving down the road in any gear if i let of the gas in gear the rpms drop to idle. I can give it gas and rpms come back up to wher i can feel the trans start to go back into gear. every thing else seem to be normal while driving, It just seems to fall out of gear (drive 3rd 2nd 1st) if I lift my foot off the gas. Any feedback whould help. Thanks.

 

This is the input sprag causing the problem. It is not holding. The transmission will have to be torn down to solve this. It will be obvious once it is opened up.