Seems to only do it it once per trip, once in awhile it won't do it. It is randomly shifting into 4th gear by itself. Does this in tip or drive. Once it does it I can shift back into whatever gear I was in. If I am in 5th and cruizing, when it shifts into 4th it will just slam into 4th. Since there is no load or decel a that time, it's a violent slam. I think I felt it try to shift at a red light the other day. This is getting annoying. I have a 517 torque converter, no codes, fluid level good.

 

That's odd.
Not a very common problem from what I've seen.
If I had to guess, I'd say that the 517 T.C. was culprit.

It sounds like the T.C. lock-up is malfunctioning.
Other than being a nuisance, I'd say your fine unless your getting codes.

If codes are present, then slipping or a non-lockup condition usually ensues.

 

I think it's electrical. I feel a click in the shifter when it happens, the same click as when you push the brake pedal down to shift out of park. It is obnoxious, I can't take it in because they will have to drive it around for quite awhile and it might not even do it. It is not throwing any codes. It will do it it once, then won't do it again until the next trip