Engine/Transmission (1994 - 1998) transmission prob

[MarkChapman]

On my way to work, no load or trailer. After about 10 miles started shifting in and out of Overdrive and trans temp light would come on. Turned OD off and seemed fine. Turned OD back on, it took about 2 mins to shift to OD then became erratic and trans temp light came on again. Complete fluid and filter change about 40000 miles ago. Any ideas? Thanks for the help.



Truck is '95 2500, auto, CTD with 193,000 miles.



Drove truck to the store, approx 5 miles. Shifted 1,2,3, OD but I don't think the TC locked up. After about 3 miles itdownshifted to 3 and would not go back into OD.

 

[ttbird]

The trans temp sensor and TPS mounted on the injection pump control shifting into OD on a 47rh transmission, as well as the computer which sends the command after digesting the sensor info. From the sounds of your situation I'd check your trans temp sensor first. If it's not working correctly it would't send the correct info to the computer and could cause to OD to lock out. When the trans is cold, sensor cold, trans should not shift into OD til it reaches a certain temp. (for some reason, I think it's about 75 F, but I'm not sure). After reaching the correct temp, OD works. If your temp sensor is failing, it might be telling computer to lock out of OD. The other culpruit is the TPS, check the forum for lots of info. If it turns out to be the TPS, which is about 209. 00 at Geno's, I think. I would replace it with a linear pot. Here's a link with alot of info. https://www.turbodieselregister.com...mission-1994-1998/156901-tps-myth-buster.html . Dnr Customs makes a kit for overdrive conversion of 1st/2nd Gen trucks located here: Transmission Upgrades : Zen Cart!, The Art of E-commerce. This is the kit I used and have been extremely happy with the results, that I would never go back to stock. It lets you control the shift and lock up of the converter by turning the knob. Just my 2 cents. Tom