Dodge ram dually auto trans gear hunting
 

Dodge Ram 3500 99, auto tansmission is "hunting" - that is it goes in and out of a high low gear hunting for what i dont know. it happens from about 45kph to 80 kph only. its really annoying. if i take off overdrive it stops but thats too much strain on on revs for that speed constant. is it electronic, chip,bad oil, speed limiter?? (I have changed over the torque converter about a year ago and it did nothing except cost a lot$$.it went away fro about 6 months without any reason, one day i started it up and took over real quick late for work, didnt even wait fro guages to warm up...i dunno man