I just bought this '96 1 ton Dually with the Cummins motor. The truck runs great and seems to shift smoothly with no problems. This was a one owner truck with only 95,000 miles on it. It has an automatic trans and is 2 wd. The problem exsists when the truck is stopped and is still in gear, the rpm's drop to around 250 and it starts to lurch and then it dies. I have been shifting into neutral at stop signs, and it seems to idle just fine. It seems to do this more times than not, but ocassionally it will hold a good idle while in drive. I talked to a buddy of mine that is a shadetree mechanic, he seemd to think it was a fuel delivery issue or a idle setting. I dropped it off at the local dealership, thinking that they would know exactly what was wrong and could fix it quickly. They called me yesterday and told me that the truck needs a new transmission, or the current trans rebuilt. $1800 for parts and a total of $2600 to do the job. To me that doesn't make much sense, maybe somebody here has had this same problem and can help me out. Any info would be great. I will probably take it to a different mechnic next week to see if they can fix it.

 

sounds more like the torque converter is trying to remain locked up. . . .but due to the low RPM's the line pressure to hold it locked up is low and it slips, but holding enough to cause this.

I dont have the schematics infront of me, but there is a mystery switch that can be used on the older 12 valves like yours to put the TC in lockup. this is something you may need to look into and see if the previous owner installed this switch.

 

Thanks, that may be the problem. I will have them check it out.

 

Lumpy...try this link, or copy and paste for a diagram and info on how to install the lock up switch.
http://www.tstproducts.com/Torque%20Converter%20Lockup%20Switch.pdf [/align]