dodge trans shift problems

From : seawalking u41606 uwe

Q: what would cause a auto trans to shift up and down when moving at 65 mph also the truck idles at a surge of 500 to 1250 rpm when parked this is a dodge 1997 2500 hd with 360 ci .

Replies:

From : roy

what would cause a auto trans to shift up and down when moving at 65 mph also the truck idles at a surge of 500 to 1250 rpm when parked this is a dodge 1997 2500 hd with 360 ci probably going in and out of overdrive. idle could be a tps. .

From : tom lawrence

probably going in and out of overdrive. idle could be a tps. yep - both problems sound tps-related. the tps will cause the trans to lock/unlock its probably the converter locking/unlocking not actually shifting between 3 and 4 and will also cause the computer to chase the idle... tps spikes to a higher voltage and the pcm immediately increases the amount of fuel anticipating more air. but since the throttle plates havent really moved the idle goes rich dropping the rpms then the pcm cuts the fuel going lean bringing the rpms up. lather rinse repeat. to the op the throttle position sensor is bolted to the side of the throttle body underneath the air intake. its the sensor on the opposite side of the throttle cable linkage. do you know how to back-probe an electrical device and check its voltage output preferably with an analog multi-meter if so you can diagnose the sensor yourself pretty easily. if not you could have a shop do it or you could gamble the $40-or-so for a new part and swap it out hoping that its really the problem. .

From : peterd

on sat 23 feb 2008 214511 -0500 roy roy@fhome.net wrote what would cause a auto trans to shift up and down when moving at 65 mph also the truck idles at a surge of 500 to 1250 rpm when parked this is a dodge 1997 2500 hd with 360 ci probably going in and out of overdrive. idle could be a tps. or torque converter lockup/unlockup on gms yea ive got a few of them too... the tps will account for both problems. not sure about dodge however. .