Engine/Transmission (1994 - 1998) New to Group - OD Question

[tugboatphil]

I've been a 1st Genner since 1994, but have recently been driving my step-dad's 97 3500. With my 93, I start out with the OD disengaged. When I reach about 45 mph, I hit the switch and I have a smooth transition into OD. When downshifting, it's the same.



With the 97, the downshift is the same that I experience in my own truck. However, shifting into OD goes something like this; I hit the button on the dash and the engine jumps up about 250 rpm for about 2 seconds. It then goes back to whatever it was to start with for another second, then it drops into OD (about 600-700 rpm).



Is this normal? There is only 24,000 miles on this truck. It has been used mainly to haul gravel in a 14 ft dump trailer. From what I can get out of him, he never takes it out of OD, and didn't even know what the switch was for. Is something worn out, or in need of adjustment?



Otherwise, it sure is a smooth ride, compared to my old beaters. Thanks for any help!

 

[USMCBay]

Start simple....

I had some OD problems for over a year.

This info fixed my problem and you may want to try it first.

Find your TPS. The black box with a 3 wire connector where your throttle cable ends. The 3 wires need to come out of the wire loom. The wires pick up milli-amps from the other wires and it really monkey's with the shift. Or at least it did mine and others too. The second thing would be to clean the TPS itself. I took the two small bolts out and tapped on it alittle and got quite a bit of black "charcoal" out. well some anyway... then a sprayed the electronics cleaner in there real good and no more problems !!!!



Would be a good first step.

P. S. I pulled the wires out almost all the way to the firewall. Pulled out 1' at first and helped but didn't solve it.

 

[DBCooper]

TBP, your step Dad's truck is acting normal. The converter has to unlock first, shift to OD, then re-lock. It won't do it if you leave the OD on and run up the gears because it won't lock the TC in 3rd with OD on. Most people here do what you do as far as keeping it out of OD until you need it. I wouldn't worry about it at all.

Dan

 

[USMCBay]

Okay reread the post and yes that does sound normal.

Sorry for jumping to conclusion!!!!

 

[tugboatphil]

Thanks for the info! I hope to be monitoring the group more often. I think I might have him talked into selling it to me.