I have a 1999 dodge ram 3500 cummins. A recently had to have the fuel injector pump replaced. the lift pump was also replaced a week prior to the injector pump. ever since the injector pump was replaced the transmission goes in and out of overdrive frequently. at between 38 and 45 miles per hour it will just go bsck and forth. at higher speeds i can feel it go off and on every couple of minutes. could this have anything to do with the new injector pump. or is it just a coincidence.

Bob in East Leroy Michigan

 

I had a filter put on my throttle position sensor wire I had that problem also out about 30 and also at 50. It felt like it was going in and out of lock up.

 

get your self a new speed sensor, cheap fix, i had the same problem with my truck and thats all it took to fix it.

 

Mine did that and it was a loose negative battery cable. Tightened and all is good.