My trans only shifts correctly when I floor it, otherwise it shifts with a violent jerk from 2nd to 3rd. It also holds first gear longer than it should. Any ideas about what it might be?

 

have you checked the kickdown linkage?

 

Yes, everything was fine then all of the sudden it started doing it. I'm now thinking that either it is a solenoid in the tranny or some check ***** are sticking and needing the higher pressure when I floor it to move.

 

First check your fluid level and condition as this is a symptom of low fluid and is the easiest to check. When was your last fluid and filter change? Late shifts and harsh shifts are often caused by a faulty vacuum diaphragm.
I would try a little K&W trans-x used according to directions and drive it about 100 miles then change the fluid and filter. If that doesn't fix the problem I would let a (GOOD) tranny shop take over.

 

Never heard of a mopar tranny having vacuum controlled operation. I know GM did.
Of course I could be mistaken.

 

Oops. Got my tranny's crossed. I have a GMC and a Dodge. Governor pressure is controlled by the linkage on the Dodge. Sorry.

 

I'll look at the linkage when it dries off outside.
After looking at it, it seems my return spring is weak. Do you think that could be the problem?