while in tow/haul when i brake to turn or slow down (coasting) to turn i feel a significant bump i think this is the t/c unlocking. I took it to the dealer and the said that was the t/c and thats normal. Has anyone encountered this same senario? Any help or comments are greatly appreciated. the truck is a 2006 slt quadcab with 5500 miles everything stock

 

Sounds like engine braking to me

 

i feel that also, i believe it is the way i brake though, but i dunno. mine is not a significant bump though. i dont worry about it.

 

i would bet it is the tc unlocking due to loss of pressure

 

it that a good or bad thing?

 

I have felt the same thing. It does it every time I have it in tow/haul mode so I think it is normal, but I would still like to know what is happening when it does it.

 

You guys really need to read your owners manual. That is the engine braking feature of the tow haul. Enjoy it it; really makes a difference if you are towing a good load.

 

Yep... when the Allison does it, people buy each other greeting cards and have Allison pride parades. When the 48RE does it, people start asking "what do I need to upgrade to get rid of this???"

 

mine has a small bump when i dont have it in tow/haul......right before I come to a stop or am about to turn. you think that is the TC unlocking also?

 

The converter normally unlocks at about 20-22mph and that's usually about the speed you're going when coasting up to a turn. Mine doesn't have any bump when it unlocks, but you can definitely feel it and hear the engine sounding like it's going to stall (almost sorta kinda).

Mine has a heck of a bump/thunk when the TC locks up in tow/haul mode though. Do you guys get that too?

 

With the jake you can EASILY tell the TC unlocks at 22mph.

FWIW...I don't get a bump/thunk...

Tony

 

When I used my brother inlaws d/max before I got my cummins you could feel the allison downshifting through each and every gear and rarely had to get on the brakes very hard. If that is what our trans is trying to do, it's not doing a very good job! It feels like 1 very hard down shift and I do not feel much of any engine braking. But I still love the truck and wouldn't trade it for anything!!!!!