I recently bought a 98 Ram 1500. 360 auto 4wd. But the overdrive is funny in it. when the truck is cold the overdrive works perfectly. but as the truck warms up it will actually kick out of over drive back down into drive, and will not go back in. Seems strange because if anything it should be the opposite, kick in only when it is warmed up. However only when its cold is when it will work. Has anyone else experienced this or have any ideas what it could be? Any feedback is appreciated. Thank you.

 

Same on my truck. OD worked perfectly until it warmed up. My trans was toast. Had to get it rebuilt.

 

Does the O/D off lite come on? Trans temp lite??

 

The overdrive off light does come and no trans temp light. it seems perfectly normal except it just wont go into O/D once it is warmed up.

 

If you push the button, does the light go out?

 

Yep. the light seems to work properly. Once it warms up and you push the button to engage the o/d, the rpms go up just a little bit (maybe a a couple hundred rpm), then it drops right back down to where they were in drive. It recognizes that i pushed the button but it just doesnt go in like it should

 

I am thinkin' a possible wiring issue. Your O/D off button is on the end of the shift lever, is it not? Wonder if the wires are shorting out..... all the button does it complete a circuit that sends signal voltage to the PCM, telling it you don't want O/D. if there is an intermittent short..... you would get that kind of behavior. Why it won't shift into O/D when it is enabled, well, that's probably yet another issue.

 

Could be. hard to say. like i said, the button seems ok, just before the trucks temp starts rising it works perfect. but once the temp does begin to go up it will kick the o/d out and wont go back in. i would think a wiring problem would do it all the time regardless of temp. when i have the money i am going to change the trans fluid and filter. but i really dont think that will fix it. seems like it could be like a temp sensor that isnt saying that the trans is up to temp. or something like that

 

Need to plug in with a scanner, and see what the PCM thinks trans temp is when it disables O/D. (might make a note of what it thinks trans temp is right before you start it as well, the problem may become obvious. )

 

Ok sorry for the wait. i got the scan tool on the truck. first code was a P0783: 3 to Fourth Shift Solenoid, No Revolution Per Minute Drop @ 3 To Fourth Shift. Then i began having another issue where the truck wont downshift into 1st gear. And it shifted erratically through town. So i scanned it again. P1756: Governor Pressure Not Equal To Target At 15-20 Pounds Per Square inch. Any takes on this? Im not sure if both the O/D shift solenoid and the Governor pressure solenoid have both simply malfunctioned, or if something has happened internally to cause them to malfuction. Anyone have any ideas for me? i hope its not trans rebuild time...