Towing with OD Off/Tow/Haul/Trailer Mode

[PANDA]

Whats the deal with towing and turning over-drive off or putting the car/truck in tow/haul/trailer mode? My dad got me doing this since I started driving, but why?

I know I can save gas with over drive, but is this safe on the truck? Say if I am towing something light like a unloaded trailer or even just a 2 place enclosed sled trailer?

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[Turbocharged400sbc]

OD is typically the weakest gear in the trans
an empty trailer shouldnt be an issue but anything more than a slight upward grade youll wanna get out of OD

if ya had a 2500 with the 4l80e id say go bonkers but your 4l60e shouldnt be pushed unless you wanna spend money sooner...than later

 

[Burtonrider10022]

Exactly. OD is just a weak gear, and OD OFF keeps the stress off it. Your call on whether or not you feel the trailer is light enough to do OD ON or OD OFF.

 

[Bub]

Iirc i think tow/haul keeps it in 3rd so the trans isn't searching between 3rd & 4th under the heavy load but i could be wrong

 

[Burtonrider10022]

It also does do that. By keeping it off the weak gear it also keeps it from shifting back and forth a shitload with every little change in grade.

It will also help with engine braking by being in the lower gear.

 

[Turbocharged400sbc]

tow/haul usually changes the pressure/apply tables and TCC settings

keep in mind OD is one of the is one of the gears that shifting/NVH issues can be most obvious so the apply and pressure are pretty light so you dont feel the 4th gear and TCC lockup. in fact the pcm never fully locks up your TCC it constantly slips it.....now put 4 people or a trailer behind it and you can see where this will accelerate clutch wear and tear.

for the most part be smart about it and you can use OD (tow/haul can retain 4th unless you manually shift to 3rd with tow/haul on) but if your at 1k or more lbs id say take it out of 4th when your on a long grade

besides nowadays at 65mph the rpm diff between 3rd and 3th is negligible on fuel economy but reducing the shift hunting from 3rd and 4th will save alot of wear and tear.

believe it or not your better going faster in 4th (e.g. shift to 4th at 75mph) as the apply pressures and engine rpm are higher to prevent it from dropping in and out of OD/3rd

 

[RICH17]

Brians Excusion tow/haul mode will hold gears longer and wont short shift. It will also downshift for more engine braking as well.

 

[Yaj Yak]

In my burban which now has over 175k on it... if it was something under like 2500lb (sled, empty trailers, etc...) I wouldn't pull with it... above that I would.

 

[daturbosix]

i pull with OD all the time, you just want to be cautious and dont let it shift down and up a million times while doing so. if you cant do that, then just keep OD off.

 

[DEEZUZ]

OD OFF while city or long grades/hills...

OD ON with crusing highway, straight roads...

 

[Handsome Jesus]

my truck defuels at shifts in tow haul and has aggressive engine braking. I feel like I would only be using it for really heavy shit though.

 

[PANDA]

oh u fancy huh

 

[Handsome Jesus]

not really. I think that's what they all do. probably has something to do with torque management.

 

[Turbocharged400sbc]

fancy......



my tq managment is (whats left of) my brain, thee right arm, and left and right legs