Towing when raining on mountain

at least with GM diesels, if you have cruise, and/or tow/haul on and/or exhaust brake AND the computer detects slip between the front and drive wheels it will almost instantly kick off cruise, and/or tow/haul and/or exhaust brake.

On older vehicles, using cruise and other functions could get you in trouble if wheels start to spin or slip because the offending function wouldn't kick off.

another thing I found interesting is that on my duramax once going downhill I shifted to neutral to see how fast I would pick up speed. What happened next was a suprise. Engine rpm STAYED THE SAME! and then went up as speed increased,it did NOT go down to idle RPM, even though the engine was indeed in neutral. shifting back to drive was as smooth as a babies butt.


Personally, other than ice or snow I use cruise, tow/haul/ exhaust brake when needed regarless of rain or not.

My owners manual for my 2018 GMC 3500, Duramax Diesel makes no mention of using the tow/haul mode or the exhaust brakes in adverse conditions. For the cruise control it only says not to use cruise control slippery conditions. Slippery conditions are up to individual interpretation.

This is all silly. Use tow/haul and exhaust brake especially on a long downhill run; sunny or rainy. If there is that much ice one the road don’t tow it at all.

With Allison Transmissions (General Motors ONLY) Tow-Haul also engages the transmission downdhift feature which will ASSIST in holding down speed on downhill runs.

It is not an engine brake and is not as effective, but it certainly helps.

The basic answer to the OP's problem is: Slow Down!

On Edit: Do you folks not realize that each manufacturer programs their version of "tow-haul" the way they want. In case you have never noticed; Chevy is different from Ford which is different from Ram.

donn0128 wrote:

romore wrote:
I would suggest the writer is trying to limit liability in case the reader messes up. If the tow haul is engaged at high speed there will be an abrupt downshift when the vehicle slows down, common sense dictates that is not a good idea on slippery roads.

Huh?
Tow haul can be engaged at any speed. Nothing happens until you alow or stop. When you start moving again the transmission will hold each gear longer to aid in bringing the load up to speed.
You really need to understand what a transmission tow/haul vs a diesel exhaust brake difference is.

Again donno, romore is correct. If you haven't had your trans abruptly kickdown a gear or 2 when running downhill and hitting the brakes (or even with cruise on sometimes) then your truck isn't working right.
The point is, the more slippery the road is, the less abrupt yours or the vehicles moves should be. TH and EB add to the abrupt moves period.
Bunch a armchair QBs here who don't understand their vehicles and apparently haven't driven in all conditions, or are at least not aware of all the things that can affect traction in less than ideal conditions.

Will any of this slide a truck sideways in the rain with a significant load in the bed? Not real likely, until you hit the right conditions.

Tow haul only alters the transmission shift points so during acceleration it holds in gear a bit longer. Dry, rain, snow will have no effect on its use

Tow haul has to be engaged on my truck to use the "auto braking" or whatever its called to keep the truck slowed down on the downhill side.

If I engage the tow/haul on my Ram at highway speed nothing happens until I slow to about 50 then there is an abrupt downshift and the ctd yells. I would rather that not happen on slippery surfaces, it works a lot better if I slow down first.

X2, BB.

romore wrote:
I would suggest the writer is trying to limit liability in case the reader messes up.

Exactly.

donn0128 wrote:

romore wrote:
I would suggest the writer is trying to limit liability in case the reader messes up. If the tow haul is engaged at high speed there will be an abrupt downshift when the vehicle slows down, common sense dictates that is not a good idea on slippery roads.

Huh?
Tow haul can be engaged at any speed. Nothing happens until you alow or stop. When you start moving again the transmission will hold each gear longer to aid in bringing the load up to speed.
You really need to understand what a transmission tow/haul vs a diesel exhaust brake difference is.

Really depends on the 'programming' used for tow/haul mode

If I am in 'D' doing less then 60 mph and push the tow/haul button the transmission WILL downshift from 4th (OD) to 3rd and then upshift when I go faster then 60 mph


Exhaust Brake...only engages when I let off of the go pedal.
But if in tow/haul AND EB...letting off of go pedal EB closes and transmission downshifts

Rain...not too worried
ICY/Slippery (snow) I would be cautious about using either