C4 must be revved before abruptly moving forward in drive

1973 Maverick Grabber, 302 auto. When i put in drive it will not move unless revved up a bit. Then it abruptly engages, even barks the tires. Reverse is the same but less rev needed. Also, the whole car shudders when revved in neutral. The engine will also drag to a stall after driving at speed and coming to a stop. I bought car this way. Because of shudder and increased stall speed, i'm thinking torque converter . Any thoughts?

 

Low on trans fluid?

 

Loose valve body bolts can cause the same.

 

Yeah, I changed the trans filter and fluid before even trying to drive it. Checked bolts on VB. Fluid and filter looked good. ODO reads 80K miles and I believe it based on overall condition.

 

lubegard friction modifier

that's what I run in all my A/T. my transmission builder puts a bottle in all his transmissions he rebuilds. My thought: if he is standing behind the rebuild and uses this, good enough for me. first time I used this in a used car transmission was A Ford Windstar van. he put in a bottle and no more converter shudder...

 

Lubriguard fixes shutter in lockup transmissions that have a clutch inside converter.

If it helps, the problem isn't/wasn't the converter, C4 has no such device inside the converter.

 

When I look up lubegaurd, says not for use with Type F ATF. Which one exactly do you use?

 

my C-4 didn't use type F. after the rebuild.

 

Vibration and low line pressure(potentially the cause for delay before revving to build pressure) could also indicate a stator and/or pump related issues. Should get a pressure gauge on it asap.

After adjusting the bands I'd also drop the valvebody and clean it up for inspection of separator plate wear and/or sticky valve movement. Stock replacement parts are cheap enough and you can also replace steel check balls with nylon while you're in there.

 

My first thoughts exactly

 

If the fluid isn't low and the valve body and filter are correct and tight it's a pump,gasket, seal rings on the pump. Probably need to do a line pressure test. Just to see what it does pour an extra quart in it.

 

I overfilled it according to dipstick. It drives pretty good now. So, what does that mean?

 

Could be wrong dipstick. Could be wrong filter/pan combo.

 

could mean it had been sitting for a while and just need driving...