Mark'sAzRam

My truck is an 08 2500 w/6 speed Aisen automatic trans. I just had this trans. installed in June by Aamco and it's their top of the line remanned unit. Supposed to be stronger than the original trans. It's been operating flawlessly since being installed until I hooked up to our 26' 5th wheel camper and tried towing. The trans. goes a several miles just fine operating with tow/haul on and exhaust brake on. I reach a stop light and then when I take back off the trans. goes to 4th gear and stays there. It won't downshift or upshift and the tow/haul doesn't work and the exhaust brake quits working. I end up running 50-55 mph at 2300-2600 rpm. Had the Aamco trans. builder get in the truck with me today and take a ride. He acknowledged it isn't operating right and when we got back to the shop he pulled the codes from the system. There were several transmission codes. Shift solenoid related and overdrive temp related. I took the trailer home and drove the truck back to the shop. Trans. still hung in 4th gear. I got a ride home and 1/2 hr later the front desk guy calls and asks if the light bulbs in the trailer are LED or old style. Says if they are LED I need to change them to old style because this can be the cause of my problem. REALLY? Well they are not LEDs and tomorrow I'm going to hook up and tow the trailer without the electrical cable connected, to hopefully rule out the trailer as the cause of the problem. They are going to have a safety vehicle follow me. Anyone here ever experienced this type of issue? How did it work out? Any insight would be appreciated. Thanks, Mark.

PS: Almost forgot. If I unhook from the trailer and wait an hour or so the trans. shifts normal. Tow/haul will work and the exhaust brake will function again.

Mark'sAzRam

Maybe this info can help someone else. Spent a couple hours today working with the shop tech and the shop owner. We towed the travel trailer and they have ruled it out as being the problem. The tech had his scanner and computer system tied into the truck's system while we were on the road and he was able to see what was happening. He thinks he will be able to get it straightened out. It's within the 90 day electronics warranty. Hope it is something that came with the trans. We had the code p0700 show up for the trans. control system. But no other codes this time.

mega-engr

Hope you figure this out and let us know the solution!

BigIron70

I had issue with Aisen trans every time I service one. The connections to solenoids were main problem. Re-crimp connection and cleared codes. Problem solved.

Mark'sAzRam

Thanks for the input. I stopped by the shop this afternoon and asked about the progress. The tech has been picking the brains of other Aamco Techs around the country. I guess they have a network they use. They are scratching their heads pretty good on this one. They don't understand why the trans. functions normal when not towing but acts up when towing that heavy load (10k lbs). To my way of thinking, the load definitely affects everything from frame to engine, trans. and rearend. It makes everything work harder.

Mark'sAzRam

It's fixed. Turns out it is quite a common issue with our 68RFE trans. The valve body solenoid switch valve bores can/do get worn and cause the problem I was experiencing. Replace the valve body and problem is solved.

mega-engr

Thank you for the update and the root cause! Glad you got it figured out and able to help others.