Converter locking question

[HowieE]

I have a 04 6.0 in my Excursion. I have heard some GM types say that the Allison converter is locked in tow/haul mode. One I question that and two I would like to know if there is a way to lock my converter manually.

I have used the BD Torque Loc in the past but have heard that is not an option for the 04 trans. Anyone got the skinny on this?

 

[KRISTOLSON]

The t/c should have almost the same lock/unlock points as the allison tranny when in tow/haul mode. The allison will not be locked all the time, neither will the torq-shift. You will definitely feel it lock up when slowing down in tow/haul, you get a ton of engine braking. Same thing with the allison. Both will minimize the locking/unlocking when in tow mode.

 

[TexasA&M]

So when exactly does the TC lock up in these trannys? The only in depth knowledge I have on auto trannies is the 700r4 that is in my '86 Chevy. The TC only locks up in OD, and only unlocks when the brakes are activated (not wired this way from the factory... it's a custom job). I also have a switch that I can override the regular operation and lock the TC in any gear or any speed.

Anyhow, how does it work in the 04-up fully electronic trannies in the Fords?

 

[Jimn8or]

A word of caution re Tow/Haul mode

Was coming down a winding, twisting hill in the rain last weekend and thought I'd use the engine to help brake the truck for the corners....well hellsbells I almost lost the truck as the downshifts in Tow/Haul mode locked up the rearend...the harder I braked the more the truck downshifted and of course the more the rearend locked. Was pretty ugly for a few very long seconds until I hit the gas and the switch to normal mode. Summed up, I won't be going downhill in the rain in Tow/Haul mode again

As for the original Q in this post; On my 200R4 [Buick]tranny there is a wire on the 'OBD11' plug that you hook up a switch to, to lock/unlock the converter at will. Perhaps the '04 trans has similar capabilities you could investigate.
Jim

 

[ktpauley]

If you get a SCT Xcal 3 with custom tunes you can get the convertor to lock in 3rd gear and up with contionous convertor lock up while downshifting. I have that in the Extreme Street tune I run as my daily driver tune. Keith

 

[KRISTOLSON]

I already pm'd this info to howieE, but doing some research, the newer 5r110 tranny cannot be jumpered into locking the torque converter. The consensus with all the people I asked was that the tranny will go into fault/limp mode if you try to do this. There are a couple of tuners that will control this tranny, but the best option I have seen was the ats co-pilot, but it is like $1500 And you are still stuck with an automatic control, no manual on/off. BD makes an AUTOLOC, but after further reading on it, it looks like it is made to lock the tc when an exhaust brake is applied. (my thought though is that you could run the signal that would go to an exhaust brake to a 12v positive and a switch in your dash, creating a manual control)

 

[FLynes]

You might also want to post this on Diesel Forum - The Diesel Stop.com and ask Mark Kovalsky. He was a Ford Automatic Transmission Engineer and helped program the 5R110, when it was designed.