99 volvo gen 1 eaton 2 pedal automatic trans issues

[bags]

About 2 months ago I filled up with  fuel, bobtailed 20 mile home and hooked up my rig and toad. 10 mile from home my rig started derating for 15 to 20 seconds and then would pick back up to speed. This happens with and without the cruise. on flat spaces, going up hills or down. I stoped and put in a gallon of power service diesel fuel and tank cleaner as per recommendation of my mechanic. I still had the same issues and assumed I needed to change my fuel filter. Ran for 300 miles and changed the filter and still had this problem. I then began to believe it was not a fuel issue. I made about a 700 mile trip with not any change, every 15 to 30 mile truck would monetarily derate then begin running just fine again.

I called a mobile mechanic and he put his computer on the truck and could find no transmission code or any other codes. He had my mechanic on the phone while reading his computer and had some issues with it dropping off. My home mechanic had no such issues. The mobile guy said he saw some weird code that he thought we allison codes but not familiar with them. Came home and my mechanic cleaned the ecm connections and found no reason to suspect and issues. He then spent 5 hours cleaning all grounds, testing and reconnecting batteries. We then got in the truck and pulled the rig for a couple of hours with his computer no codes and had no derating issues. I then hooked up the trailer and toad for another trip and had the same derating issues. He suggested I take it to a transmission shop and they found no codes (truck only). My next step is to hook the entire rig, take the transmission mechanic for a ride with his computer attached and see what happens. Of course the transmission mechanic is 2 hours round trip and I would like to avoid this trip. I asked the transmission mechanic about pulling and cleaning all the transmission sensors and he said that would involve 6 or 7 hours labor and he hated to do that. Has anyone experienced this issue.

The key is that I only have a problem when pulling the rig and toad. I even disconnected the toad light cable and still had the same issues. No codes are stored in the ecm.

Any and all help would be appreciated.

Thanks in advance

JB 

[lappir]

You have a two pedal auto shift in a 1999? My 2001 has the 3 pedal Eaton autoshift.

I may have had a similar issue, but my truck actually would die and I would have to stop and after a bit it would restart and go 15 min or so. 

First time it happened spent over 1K at a Volvo dealer before they found the 15 cent wire and repaired it. Second time it happened I was in Kansas and the wire broke off at the battery . Fixed that on the side of the road and then took the truck to my mechanic who refreshed all the wires going to the batteries. Hope that works for a bit. 

I can't go out to take a photo tonight, but maybe tomorrow if you need one to show the wires that caused the issue. 

 

Rod