samahi72

98 Cummins, 4 Speed Automatic. 67K original.
I bought this truck thinking that I was getting a cream puff and for the most part it is, except for some nagging issues with the tranny. To begin with, it had a bad torque convertor. So I had that replaced and while the tranny was out, they serviced the tranny, new filter and amsoil synthetic fluid, replaced the seal between the tranny and transfer case, $1,800.00. Now the tranny will not shift between 3rd and 4th, you can feel it trying but it just doesn't get there. I have read somewhere on this forum that there may be a service bulletin dealing with this problem. The tranny guy initially said there wasn't any connection between my current problem and what they did. Perhaps not but it sure seems like a strange coincidence. I noticed the current shifting problem within a couple hundred miles after the tranny work. It could have been there right after they worked on it and I just didn't notice it. HELP please.

BBWD

You might start troubleshooting this by having the shop that did your work run a check the TPS that is located by the injection pump and controls the shifting. The TPS is a "sealed unit", but over time dirt can work its way in past the shaft and affect the voltages this unit sends out that tells the transmission when to shift. They can be reworked (do a search on TPS). If you need a new one they are about $150, Cummins part number 3930318. This was for a 98' 12valve.


John (DH)