![]() ![]() Not many miles on it yet but so far so good. The transmission has shifted great/very smooth ever since the reprogram. I picked up the truck and drove it in normal mode for about 175 miles and then with the 5th wheel about a total of 400 miles in the Virginia (I-64 up over the blue ridge mountains, Afton mountain) for a camping trip. He also stated that Chevy engineering told him that something during the trans adaptive learning process must have gotten corrupted. I suppose that would be a new download to the TCM. Chevy engineering department instructed the shop supervisor to reload the adaptive learning software/code. As we know the allision transmission is an adaptive learning transmission. My truck transmission initial torque convertor lock-up was 65 PSI. The pressure should be about 20-25 PSI at initial lockup and slowly increase to about 75-85 PSI as RPM increases. The dealership shop supervisor stated that Chevy engineering told him to check the pressure to the torque convertor at initial lockup in first gear. The dealership shop supervisor told me that the 10 speed Allison transmissions are so new, Chevrolet has told them not to go into the transmission without calling chevy engineering department and discuss problems encountered. The following week the dealership shop supervisor took a ride with me and I demonstrated the problem and discussed corrective action. ![]() We discussed the problem and I made an appointment has he suggested. Called the dealership and requested that the shop supervisor give me a call because he asked me to after the first trip to the dealership if the problem persisted. At least I could demonstrate the problem at the dealership. So the torque convertor lockup was harsh. I started in first gear and slowly accelerated and the truck jerked and I was still in first gear. Pulling the shifter down to "L" the trans can be shifted manually. Everything shifted fine until the trans came up to normal operating temperature then I could reproduce the "hard shift". When using "Tow/Haul" the transmission starts in first gear and the torque convertor locks in first gear. The site stated when the truck is driven in "normal" mode the transmission starts off in second gear. I did find a couple of web sites that explained in lay-man terms how this allision 10 speed works. Again when driven in "Normal" mode it shifted fine. After we returned home, I started searching the internet to see if anyone else was having a this issue. All the rest of the shifts were smooth/great. So the next time a towed the 5th wheel in "Tow/Haul" mode, after about 30 minutes, it started to shift hard again what appeared to be from first to second gear. Later on, I took the truck to my local Chevy dealer and they could NOT reproduce the problem. ![]() The transmission temperature never got over 156 degrees. The transmission would shift very hard what appeared to be from first to second gear. The transmission problem started around 2100 miles towing the 5th wheel in bumper to bumper traffic inching along on the interstate outside Washington DC in 100 degree heat. My total combined weight is 22,600 pounds. I use the truck to pull a Heartland Bighorn 14K 5th wheel. Finally bit the bullet and upgraded from my 20 HD, crew cab, 4X4, LLY Duramax, 6.5 bed length, SRW to a 2020 Chevy High Country Duramax, crew cab, 4X4, 8 foot bed length, SRW in May 2020. ![]()
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