tow/haul '05 cummins

today was the first day that i towed heavy with my '05 big horn (i definately bought the right truck!). when i switched into tow/haul mode it stayed in drive a little longer, but it still shifted into overdrive. is this normal, or is tow/haul just a setting to keep the torque converter unlocked or something? thanks,

Reply to
Nathan W. Collier
Loading thread data ...

Normal. In '05, the tow/haul mode changes the way the transmission shifts (keeps the T/C locked longer, extends gear ranges, and will downshift to assist in braking), but O/D is not locked out. With the 48RE, it's not a concern.

Reply to
Tom Lawrence

sweet, it caught me by surprise when it shifted into overdrive.

what about the '04.5?

i also noticed the downshifting. good job dodge!

Reply to
Nathan W. Collier

In '04.5, (and '04 as well, I believe), they simply renamed "O/D OFF" to "TOW/HAUL", because less-than-informed buyers would say, "well, the other maker has a tow/haul thingy on their transmission - do you?"

It took them damn-near forever, but I'm fairly certain the '05s can accept an ECM flash to allow approved, warranty-covered use of an exhaust brake. That might be something you want to look into if you plan on pulling heavy through the mountains.

Reply to
Tom Lawrence

pretty much what i thought. what would it take to make an '04.5 perform like the '05? a controller swap? a flash?

what do those typically sell for? initially i really wanted an exhaust brake but since playing with my prodigy im confident in its efficient and effective braking. if its not ridiculous id probably add an exhaust brake but if its ridiculous ill rely on my prodigy.

Reply to
Nathan W. Collier

A BFH and a blowtorch :)

Around a grand...

Reply to
Tom Lawrence

the PCM boosts line pressure in 'tow'

since line pressure is up, it takes more governor pressure to move the shift valves

so shifts are firmer and delayed a bit

converter should lock in OD or in 3rd if OD is cancelled, in 'tow' mode

G

Reply to
TranSurgeon

thats not to bad, certainly not what i expected. ive seen the literature on the jacobs brand. any others?

Reply to
Nathan W. Collier

what would it take to make the '04.5 perform like the '05?

Reply to
Nathan W. Collier

someone at Mopar to get off their ass, figure out the 'new' strategy, then get EPA approval for the programming

never happen

Reply to
TranSurgeon

if the '04.5 48RE and the '05 48RE are mechanically the same, what parts would i need to buy to make them perform the same? specifically what makes the '05 act differently than the '04.5?

Reply to
Nathan W. Collier

the ECM programming, most likely

valve body's are identical

Reply to
TranSurgeon

sweet. is this something i could get reprogrammed at a tranny shop or is this a dealer only issue?

Reply to
Nathan W. Collier

any 'flash' of the OEM system has to come from Mopar

Reply to
TranSurgeon

That's the only one that's warranty-approved (for whatever that's worth), but I've always ben partial to PacBrake. The big downer for me about the Jacobs is that it uses a vacuum pump to activate it. While that in itself isn't a big issue, the fact that the vacuum pump mounts in the accessory drive, and therefore requires a special, longer serpentine belt, could make emergency replacement an issue. The solution here is to get two belts at the time of install, and keep one under the seat.

BD Power and Banks are also popular choices for exhaust brakes.

Reply to
Tom Lawrence

if you are talking about an exhaust brake, the '04.5 will not be approved by dc for one. the '06 auto is approved for one. the '05 will be but it will take a while, probably some time next year. the software for the '05 has to be written for the ecm and dc is simply in no hurry to do that. the ecm in the '04.5 is not large enough for the software and likely can not be changed out, it is a whole different cat.

that doesn't mean that you can't put an exhaust brake on an '04.5, you just void your warranty if you do.

Reply to
the guy

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.