8.1's with Allison's can't get the TM turned off from what feedback I got. CaptRon had a guy locally try to turn it of on his 8.1 2500hd. Couldn't do it. Or I guess I should say the guy that did the tuning couldn't. That same guy turned it off on his 2500 Yukon, but those came with 4L80e transmissions.
People wonder why Larry and my 8.1s run a cable throttle that 8.1s never used from the factory. Torque management is one. Second is there is less to fail in the boonies.