Low Range when towing 6000 lbs on really steep backroads? (1 Viewer)

[John E Davies]

In the past I sometimes used Low in my heavy LX450 when climbing or descending seriously steep, low speed gravel and paved roads with a 750 lb trailer. I did not use any of the lockers on pavement, I locked the center one on gravel. It really helped both power and control and I never needed the brakes going down.

I’m talking about 12+% grades with tight switchbacks, no other traffic.

Fast forward to my 2013 200 towing a 3 ton Oliver.

Will I hurt anything in the drivetrain by using Low on really steep roads, paved or not?

Should I stay out of the two OD gears or are they already disabled?

Will I hurt the transfer case due to heat buildup?

Does anyone else do this and can you comment?

I did read an Aussie caravan article on towing a similar sized trailer off pavement and the author commented that they used Turn Assist to help navigate switchbacks. I am pretty sure I don’t want to tow a $60k camper onto that type of road.... OTH I can’t find any other info about this. Other than boaters using Low to retrieve their boats up loose or wet ramps.

The hill start assist system is an absolute pearler if you’re tackling steep terrain, and Toyota’s Crawl Control helps take the guess-work out of tricky ascents and descents where you’d rather focus on the precise steering input rather than juggling the brake and accelerator to maintain speed. There are three selectable speeds you can choose from, depending on the steepness of the terrain. Turn Assist is also available to help tighten up the turning circle by locking the inside rear wheel, something that seriously comes in handy towing down tighter tracks

Holy cow...!

LandCruiser 200 Altitude Special Edition: Tow Test

I wish I had that wonderful diesel engine.

I have had the Oliver for year but I will be taking it into the Natinal Forests for the first time in Spring. I am in the process of installing a Stone Stomper, mudflaps and under chassis rock skirts... woohoo!

Thanks,

John Davies
Spokane WA

 

[OregonLC]

You won't hurt the truck. If anything you'll help it by reducing heat build up in the trans. I would do that exact same thing rather that allow the torque converter to try to overcome a too-tall gear ratio for the application.

And if you're an infrequent 4Lo user having the actuator exercised more frequently will keep it happy too.

 

[TeCKis300]

John,

You're absolutely using low range in the proper manner. That's how you do it!

The measured and controlled torque of low range is much preferred over using high range in these situations. And I agree with OregonLC that you'll be putting a lot less stress on the motor, torque converter, and transmission. The driveline and brakes likewise will be stressed less as there's less lurching with the control of low range.

First thing I do upon getting to the campsite is put her in low range. Oftentimes, the pad is irregular and not level. I rarely lock the center diff as that's for very low traction situations (e.g. sand), or where a wheel might lift in the air over irregular surfaces. Usually I'm maneuvering in these situations so an open diff is more helpful.

 

[Romer]

I downshift to 2, 3 or 4th gear depending on the grade. Since you have to stop and put it into Neutral to switch to Low range, bot sure why you would do that. Is this just a semantics difference here?

 

[TeCKis300]

With a 12% grade and hauling that kind of load, 1st gear may not even provide enough engine braking for the low speeds. Definitely a job for low range.

 

[John E Davies]

I downshift to 2, 3 or 4th gear depending on the grade. Since you have to stop and put it into Neutral to switch to Low range, bot sure why you would do that. Is this just a semantics difference here?

Torque multiplication. In low range you have seriously more available power and compression braking. Yes you have to stop dead to switch over. I am talking about isolated 15 mph forest roads with no traffic, stopping is not a problem. ... the problem is getting up those steep loose switchbacks.

Thanks everyone for the other replies.

John Davies
Spokane WA

 

[GordJ]

Just something in my experience, if you use crawl while towing it will apply trailer brakes every time the abs cycles. Even with a modern controller my trailer brakes heated up.

 

[TeCKis300]

Just something in my experience, if you use crawl while towing it will apply trailer brakes every time the abs cycles. Even with a modern controller my trailer brakes heated up.

Crawl doesn't necessarily apply trailer brakes, directly at least.

Trailer brake controllers are generally inertial based. Which means they use an internal accelerometer to sense braking motion, and apply trailer brakes proportionately. Problem is crawl works on a PWM (pulse width modulation) bases, in a herky jerky fashion. The trailer brake controller is likely falsely sensing the momentary jerks as braking, and thus applying the trailer brakes.

You can likely reduce the gain on the controller to minimize trailer brake actuation.

What type of controller do you have?

 

[Romer]

Torque multiplication. In low range you have seriously more available power and compression braking. Yes you have to stop dead to switch over. I am talking about isolated 15 mph forest roads with no traffic, stopping is not a problem. ... the problem is getting up those steep loose switchbacks.

Thanks everyone for the other replies.

John Davies
Spokane WA

Ahh that makes sense. I had my mind on the steep highway paved roads here in Colorado

 

[GordJ]

Crawl doesn't necessarily apply trailer brakes, directly at least.

Trailer brake controllers are generally inertial based. Which means they use an internal accelerometer to sense braking motion, and apply trailer brakes proportionately. Problem is crawl works on a PWM (pulse width modulation) bases, in a herky jerky fashion. The trailer brake controller is likely falsely sensing the momentary jerks as braking, and thus applying the trailer brakes.

You can likely reduce the gain on the controller to minimize trailer brake actuation.

What type of controller do you have?

I’ve the P3 and the “boost” seems to apply some braking repeatedly.

 

[TeCKis300]

The P3 boost feature runs off the brake lights coming on. Crawl uses the ABS system, but I'm not sure if the brake lights come on? If they do, then yes, that will interact with boost. I'm sure you know you can cycle through boost function to turn it off.

 

[Dan Higgins]

Ditto what everyone else has said about using low range. I tow a 6K# travel trailer. Never considered CRAWL unless I’m going over a tough spot off-road and I don’t tow off-road.