I'm driving a 99' 2500 2wd longbed with a automatic that won't shift out of low gear. It has 115,000 miles of job site driving with only occasional loads. I have tried all the suggestions that I can find on the forum's but so far no luck. I have a OBD II reader and have no codes showing. About 5 weeks ago I did have to replace the crankshaft position sensor( based on a code). I have pulled the pan and filter (no metal or crud) and refilled with proper fluid, even tightened the bands -no change-. I replaced the trans. relay and reset the throttle position sensor just like the lister's recommend but this didn't help either. Any suggestion would be appreciated!
Mark

 

You really need to get the codes read.
It may be the gov. pressure transducer. The computer thinks the truck is not moving if this transducer is out. Thus won't let it shift.

 

J-Fox,
Thanks for the response. Ithought I might have erased the code pryor to trying to read them. Hoohed up my OBD reader after driving for awhile but no codes are displayed. I think my reader is idiot proof but got the manual back out. Where is the gov. pressure sensor located?
Mark

 

It's on the valvebody, you will need to drop the pan. And have about $150 for the two- transducer and sensor.

 

Another guess is the trannys output sensor? If its reading 0 you wont shift either?
Mine would intermitantly not read and the tranny would shift into low thinking the truck was stopped? Just a thought?
Good luck
ratsun

 

Just a few question that came up as I reviewed the posts this morning.
1)The valve body with solenoids and sensors appears to be a unit, can I purchase this as a package and install it myself?
2)If so does it require any adjustments or calibration?
3)If one off these sensors is bad shouldn't it result in a code?
4)If one of the internal clutches has gone bad would it result in visable trash in the pan?

 

I cant answer any of you ?s other than my bad output sensor wasnt causing any codes. Maybe some one else that knows trannys can help you more.
Good luck
ratsun