Diff lock on downhills? (1 Viewer)

[swild]

Two questions regarding going down steep sandy/gravel sections like Diablo Dropoff:

1. Would it help to be in 4LO?
2. Would it help to lock the center diff?

 

[HVLA]

I dont see how locking the diff helps in downhill, but 4LO absolutely helps and I use it any time I encounter a steep downhill while off pavement. And I use manual shift to hold in a lower gear.

 

[r2m]

Yes and yes. Try to stay off your brakes.
Also, if you have it, use your DAC. It will help with both engine and wheel braking to maintain an even downhill decent without a lot of drama.
NOTE: If you've never used it before be ready for a LOT of noise that may sound like you're breaking things. But it's okay, it's supposed to sound like that.

 

[r2m]

I dont see how locking the diff helps in downhill, but 4LO absolutely helps and I use it any time I encounter a steep downhill while off pavement. And I use manual shift to hold in a lower gear.

It keeps ALL the wheels tied together so a rear wheel won't want to free wheel while a front wheel is engine braking.

 

[Rednexus]

You will want the center diff locked for off-road at more or less all times. Otherwise, you may end up with a mis-match in wheel speed between the front/rear axles if one either has a wheel off the ground or is on a looser surface in the other. If the diff is open, it may send power to the axle with the least amount of traction, rather than splitting it between both. I lock mine once I get on the dirt and just leave it locked until I'm back on a improved road surface. I've noticed the reduced performance the few times I've forgotten to lock it.

 

[K Dub]

Yes and yes. Try to stay off your brakes.
Also, if you have it, use your DAC. It will help with both engine and wheel braking to maintain an even downhill decent without a lot of drama.
NOTE: If you've never used it before be ready for a LOT of noise that may sound like you're breaking things. But it's okay, it's supposed to sound like that.

Plus one for DAC. I really can't stand the noise it makes, and it sort of takes the "fun" out of a difficult decent, but I've been in spots where I'm not sure I would've survived without it. But take R2M's advice and give it a try in a non-critical setting before you really need it.

 

[WTITW]

4lo yes for improved ratio on engine braking. Diff lock? Doesn't that only come into play when there is a positive power differential between front and back?

I only use my center locker when I think I'll need it. It binds up all the time and it's always a pain to unlock if I havn't driven 25 yards in a straight line. I only use it when I think I'll need the traction, and only on uphills.

DAC is not an elegant solution to "oh s***, should brake now or not???" It just keeps you from locking up and sliding on very steep descents but I've never found it more useful than my foot and the clatter so annoying.

 

[WTITW]

It's crazy how fast those AWD full independent vehicles lift a wheel off the ground in an off-camber sitch. The articulation difference between the shots of the 5th gen and the AWD's is pretty immense. Having no traction due to poor articulation AND no 4lo would up the challenge quite a bit.

 

[Acrad]

I found DAC always too fast... I like the slower speeds of crawl... DAC is basically locked in at highest crawl speeds

(3-4MPH with DAC versus ~1MPH on slowest crawl speed)

460-Add Crawl Control (CC) and Multi Terrain Select (MTS) to 2010-2019 models/all trims

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MTS also offers up different ABS "Braking" algorithms while off-road

 

[Rednexus]

4lo yes for improved ratio on engine braking. Diff lock? Doesn't that only come into play when there is a positive power differential between front and back?

I only use my center locker when I think I'll need it. It binds up all the time and it's always a pain to unlock if I havn't driven 25 yards in a straight line. I only use it when I think I'll need the traction, and only on uphills.

DAC is not an elegant solution to "oh s***, should brake now or not???" It just keeps you from locking up and sliding on very steep descents but I've never found it more useful than my foot and the clatter so annoying.

I've ran it locked for miles and miles at a time while wheeling. Always unlocks quickly. Binding is no worse than any other 4x4 vehicle. It's very noticeable if I try to climb or descend without it.

 

[K Dub]

It's crazy how fast those AWD full independent vehicles lift a wheel off the ground in an off-camber sitch. The articulation difference between the shots of the 5th gen and the AWD's is pretty immense. Having no traction due to poor articulation AND no 4lo would up the challenge quite a bit.

My mother in law has a Highlander with DAC. I imagine it's similar to ours in how it uses ABS, but without our lower gearing. She's never used it, or even tested it out so I have no idea how effective it is. I've spent a lot of time in Subarus and other crossovers and got quite used to lifting a tire. Without a center diff lock you might get beached with one tire up. ATRAC and a solid rear axle are game changers, for sure.

 

[Acrad]

I haven’t look at hardware of Highlander to see if it leverages vacuum booster for braking or electro/hydraulic like the 460.

 

[WTITW]

It's very noticeable if I try to climb or descend without it.

I get it. Downhill distribution of engine braking when a tire lifts would be aided by the locker when you lift a wheel.

Maybe I should use it more. Maybe it wouldn’t stick so much if I did.

 

[WTITW]

Really like this guy. All facts and no BS. No narcissistic self deprecating jokes or click bait. In other words he stays off my turf.

 

[swild]

Really like this guy. All facts and no BS. No narcissistic self deprecating jokes or click bait. In other words he stays off my turf.

Pretty solid video. Looks like I'll be using 4LO, locking the diff, and using MTS and Crawl Control. Thanks, guys!

 

[Acrad]

If you got sharp turns or switchbacks going steep downhill I'd lay off the locks in the those specific areas

 

[Rednexus]

Really like this guy. All facts and no BS. No narcissistic self deprecating jokes or click bait. In other words he stays off my turf.

FYI that appears to be for axle lockers, not a center differential lock. When the CDL in a GX is locked it functions just like any other 4x4 - including the Ranger in that video. GXs did not have factory front or rear axle lockers, just the center differential lock which allows (when unlocked) the front axle to spin a different speed than the rear.

 

[swild]

FYI that appears to be for axle lockers, not a center differential lock. When the CDL in a GX is locked it functions just like any other 4x4 - including the Ranger in that video. GXs did not have factory front or rear axle lockers, just the center differential lock which allows (when unlocked) the front axle to spin a different speed than the rear.

It would still be beneficial to lock it though, right?

 

[Rednexus]

In my experience yes.

 

[Acrad]

Road conditions like snow/ice & steep often lead me to keep open unless it is dead straight down