Autotrans downshift

[RobertGray]

I need some help with a transmission problem, I live in Asturias, Spain where I own the only Dodge in the province and further I've not found any automatic transmission specialists. There is a Cummins service centre where the truck is having an engine oil leak fixed. The problem with the transmission is that as I take my foot off the throttle it shifts down to third at any speed, when I put my foot down again it changes back up into fourth. In other words it happens on overrun and is otherwise normal. This problem started with the the onset of very wet weather and has happened before with very wet weather. I also suspect the oil leak which has left the underside well rust proofed. At present the speedometer is behaving as normal though I have had problems with it in the past but after cleaning the shaft on the speed sensor and tightening the nut up carefully it has been fine for the last six months. The local mechanic is excellent but only 0. 1 Spaniards drive automatics and we need some help. The truck is a standard Dodge Cummins D250 with Auto trans



Rob

 

[JLEONARD]

That sounds an awful lot like the TPS needs adjustment. That is the unit attached to the injection pump that controls the shifting. You can find how to adjust it on line.

 

[RobertGray]

Many Thanks for quick reply.

Whats a TPS and where on line to you find out how to adjust it?

Rob

 

[Tippin Spotted Cow]

Here's the instructions from the PDR Diesel website on how to adjust the TPS: PDR Diesel Inc. The turbo diesel performance specialists! - 1st Gen TPS

 

[hdm48]

I had this very thing happen to my first gen and it was the TPS. A simple adjustment cured it.

 

[cerberusiam]

Yup, the symptoms sound sooo familiar as does the cure.