06 48 RE shift modes

[ACF]

I have an 05 and was wondering when looking at the 06 48 RE the other day. I see that they now have the O/D lockout along with the TOW/HAUL feature... ... ..... however they use the same button on the end of the shifter. My question is what is the sequence that one gets into and out of O/D and TOW/HAUL mode? It would make sense that when you hit the button you first get T/H then get O/D off. By hitting it again one should get O/D back and then with one last push the T/H turned off, is this correct? By the way and news on getting any of these features on the 05 48 RE... ... ... ... along with the exhaust brake capability? Thanks.

 

[BHolm]

You have it right... think of it as three positions, normal mode, T/H mode and O/D off mode. You scroll through them with the button. You from normal, to T/H on the first push and T/H to O/D off on the second push and back to normal on the third.



It works quite well with the exhaust brake. If I am just coming down the mtn empty with the ex-brake on and hit the button from normal to T/H the trans will drop from 4-3. The only irritating part is if you are towing and did not engage T/H before you got up to speed, engaging it will drop the gear for a few seconds before the computer realizes you are at light throttle and shifts back up to fourth. It doesn't take long to get the hang of it and the T/H, O/D off is an improvement over previous trucks. I still have an '03 with the O/D off only button and I had an '05 with the T/H only button.

 

[ScottLewis]

Shift pattern of the button is:

First push is Tow/Haul on, second push O/D off, next push back to O/D.

This makes it impossible to turn off Tow/Haul without going through 3rd, disconcerting at 65. On the '06, turning the Jake on effects a temporary downshift, at least at some speeds. I'm still figuring that out.



Can't speak to developments for the '05s.





Dan

 

[BHolm]

On the '06, turning the Jake on effects a temporary downshift, at least at some speeds. I'm still figuring that out.



Can't speak to developments for the '05s.





Dan

I am pretty sure turning on the Jake doesn't cause any gear changes. What it definately does do is lock the torque convertor. That in many cases feels like a gear change. I would bet that is what you experienced, the TC has to be locked for the Jake to work. Turning the Jake on will signal the ECM to immediately lock the convertor before it closes the flap in the exhaust.



I am starting to wonder if the updates for the '05s will ever happen

 

[HBarlow]

I agree with BHolm above but understand why Dan made his statement. Mine does the same thing. Turning on the exhaust brake creates a transmission mode change in my truck as Dan reported but I wasn't sure if it was simply locking the convertor or downshifting. If the EB is off the truck will coast and freewheel when I lift my foot from the throttle. I notice the difference immediately and when I turn on the brake the transmission locks the convertor which feels like a downshift.



After 52k miles I still have great difficulty figuring out what the 48RE is doing.



Harvey