ramitred

I know this subject has been covered many times but I can only seem to find threads that apply to older trucks. A couple of years ago I had the entire trans replaced with a Goerand(sp?) trans with a billet flex plate and triple disk converter. Lately it intermittently starts hunting at speeds between 45-60 mph. It does not seem to do this when on cruise control. I'm not sure if it's the torque converter lock up or an overdrive issue. When it started this a few months ago I cleaned all electrical terminals etc and it seemed to fix it...temporarily.
Any thoughts/input would be appreciated!