ok so I'm new to the famous duramax allison combo. converted from a Ford man. I have a cc/sb 4x4 2500 single tow tune full exhaust and intake egr delete all the basics. roughly 150,000 miles and love the truck. my issue is this just recently it's started down shifting from 2nd to 1st extremely hard. it feels like it jumps into neutral and slams into 1st and sort of stalls and lunges forward upon stoping. doesn't matter if your in tow haul or not. empty or loaded it does it the same. I have a cel on and according to everyone who has pulled codes says nothing related to tranny. it only shows glow plug circuit fault for 3 and 5. trucks just been serviced fully serviced every filter changed and every ounce of fluid flushed. and still is have same issue. Danville performance did all my mods and dyno tuning
06 lbz allison help
- Thread starter edw9043
- Start date
torque converter lockup not releasing correctly!
mine will do this when in tow mode and have to stop really quick!
tc in tow mode stays engaged during down shifting and acts as a brake and it disengages at second to first shift but slowing faster than it preforms this move and you get a slam in to first. thought i broke something first time it did it on me!!
in normal mode the tc lock up is only engaged during acceleration and disengages when you foot is off pedal and slowing or coasting
i would bet you have some issue with the tc switch in the alli itself! or you tc is going bad, its just not throwing a code
good luck!
mine will do this when in tow mode and have to stop really quick!
tc in tow mode stays engaged during down shifting and acts as a brake and it disengages at second to first shift but slowing faster than it preforms this move and you get a slam in to first. thought i broke something first time it did it on me!!
in normal mode the tc lock up is only engaged during acceleration and disengages when you foot is off pedal and slowing or coasting
i would bet you have some issue with the tc switch in the alli itself! or you tc is going bad, its just not throwing a code
good luck!
Our lly does the same thing all the time. The tow mode doesnt work anymore too
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according to my trans guy it's a flow issue apparently its a common issue with trucks that tow like I do constantly I honestly couldn't tell you he replaced valve body and installed shift kit and works perfect also he tuned my trans and it all works flawless. put 2300 miles on it and no issues