Steep Grades

[VolFF]

I am leaving soon for a trip to Mount Washington NH, and have plans to drive up the Mount Washington Auto Road with my 2006 4Runner V6 4x4. The road is 12 to 22 percent grade fo over 7 miles. They recommend going up and down the road in 1st gear. Would the 4Runner be happier in low range, letting the tranny do what it wants to do to climb? Am I just over thinking this and should just go up in 1st gear?

 

[boston_kevin]

Yes. Shift down and let the tranny control your speed, especially with steep grades (like the auto road on Mt Washington). Stay out of overdrive as you are climbing because the tranny will hunt for gears based on the RPM, them downshift to get back up to speed. 1st gear may be a little too slow, especially with the 5 spd. I wouldn't go any higher than 3rd, and downhill, probably keep it in 2nd or 1st to maintain control and minimize braking.

 

[jimsi]

I agree with downshifting. You didn't mention auto or manual tranny. If it's auto then selecting 4 will disengage the overdrive and the 3-2-1 will work as selected...so dependent on your speed I would take it out of D and select the appropriate gear.

If you are thinking of using 4Lo on the 4x4 selector you probably would not use this to go up a hill. It's for low speed 'crawling' or pulling something out (i.e boat trailer on a wet\slippery ramp)

 

[JP4RNR]

I agree with downshifting. You didn't mention auto or manual tranny. If it's auto then selecting 4 will disengage the overdrive and the 3-2-1 will work as selected...so dependent on your speed I would take it out of D and select the appropriate gear.

I beleive there is no manual transmission option for the 4th Gen 4Runner

 

[Baba Booey]

I've always been under the impression that 4-Lo is much easier on the tranny when driving at slow speeds - even if it isn't absolutely necessary for the given situation.

Isn't it better to be in 4-LO when wheeling at very slow speeds even if 4-Hi is all that is needed traction-wise? I thought 4-Lo allows the tranny to operate at cooler temeperatures.

If this is true, then using 4-Lo while ascending/descending Mt. Washington may be a good idea.

 

[boston_kevin]

4Lo is for very low speeds (i.e. less than 15 mph). The V6 in either 2WD or 4Hi should be fine if you downshift to 2nd or first to maintain speeds downhill. Uphill 2nd or 3rd should be fine.

 

[Koz]

You don't need low, just use the lowest gear that will maintain a safe speed.

Koz

 

[VolFF]

Thanks Guys!

thanks to all who responded!

My 4Runner (2006, V6, auto, 4x4) made easy work of that climb and the downhill wasn't bad either. I ended up using 1st or 2nd gear depending on the speed that I needed to maintain to round corners etc, keeping the motor at 2-3,000 rpm. They suggest no A/C because overheating is so common - 'forget that' my wife and kids wouldn't have that. A/C blasting temp gauge never moved!

The way down, started using 1st and used the tranny to slow the truck, with the brakes, then found it was holding too slow, and 2nd not slow enough. after getting past the hairpin turns, with no guard rails and shear clifs, I started to just use the brakes. a brake job is far cheeper than a tranny job, and the brakes were doing fine with no noticable fade. half the way down stopped in a turnout (scenic overlook) where there were 2 cars with the hoods up due to overheating. This was well after I started primarily using the brakes on the way down, and no smell was notcible (until I stuck my face in the wheel and then just barely). Got to love the 4 wheel disk brakes with massive components!

this thing is an amazing truck! I cant imagine how the V8 would have handled it.