I don't generally lock the center diff until I am in a situation where wheel spin might occur, because maneuvering in tight twistys or switchbacks is easier without it locked. I'm a pretty experienced wheeler though, so YMMV.
Diff lock on downhills? (1 Viewer)
- Thread starter swild
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My rule of thumb is, if I would use diff lock/4Lo on the uphill, I'll probably use on the downhill because you'll have many of the same advantages regardless of which direction you're facing.
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re_guderian
SILVER Star
Crawl Control is the bomb on downhills. Like you're glued to the ground.
r2m
Richard
Whenever I unlock my axles (for the new folks on here, I have front/rear ARB lockers too) and center diff lock, I always drive in reverse about 20 feet (off pavement) or so to "un-wind" the system and let it all reset. I know many say one doesn't need to, but being a little "old school" having to do that with manual locking hubs, for me it's a habit.
r2m
Richard
Absolutely agree about the speed of DAC.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
CLICK ME: =crawl']Crawl Control and Multi-Terrain Select (MTS) retrofit on '10-'19 GX 460 / all trims Crawl control and/or MTS can be added to any '10-'19 GX 460 regardless of trim. MTS is not available in stock US models in North America except for Canadian top tier models. Crawl Control was...forum.ih8mud.com
MTS also offers up different ABS "Braking" algorithms while off-road
The few times I've used it, I still felt like I needed to tap the brake pedal a little. Considering I've regeared my axles, I more often just use 4Lo with my diff's locked when descending a grade.
- Thread starter
- #27
What about Diablo Dropoff from the video in the original post? There’s no tight twists, it’s pretty straight, right?
I pretty rarely have problems with mine locking/unlocking. I just engage it while driving in a straight line and it pops right in and out. Usually within about 3-4 seconds tops. The only issues I've ever had have been when I've done it outside of going straight....then the F and R axles are turning different speeds so it might get hung up for a second.
My rig does have almost 187K on it so it might be "broken in" a bit. But, it also locked/unlocked effortlessly at 135K when I bought the rig. I also use 75W90 synthetic gear oil (Mobil Delvac) in the TC.
I use DAC all the time. I used it coming off of Engineer Pass in CO (towards Ouray) and had it on for long periods. Probably 5+ minutes just riding it down. Somewhat surprisingly, my brakes didn't get hot at all! It's a pretty good system IMO and I'm impressed that it somehow keeps the brakes cool. I prefer it in rough stuff relative to just running in 4LO 1st gear as my rig can "run away" a bit otherwise.
I
I wheeled for many years with an Isuzu Trooper, which had an old-school part-time 4WD system, which is effectively like having a locked center diff all the time. The only time I would really got bound up was places like Moab, where the sandstone offers even more traction than pavement, so you would experience the tires scrubbing and releasing on tight turns, resulting in some oversteer. You get used to it. But on the GX you can unlock the center diff and render it a non-issue.
I think in general, including a loose downhill like that, the key thing is whether or not you will be lifting or spinning a tire. If so, it would help with control to have the center diff locked. In that particular case there would be no harm in locking it, as your tires won't bind up in that loose stuff anyway.
I wheeled for many years with an Isuzu Trooper, which had an old-school part-time 4WD system, which is effectively like having a locked center diff all the time. The only time I would really got bound up was places like Moab, where the sandstone offers even more traction than pavement, so you would experience the tires scrubbing and releasing on tight turns, resulting in some oversteer. You get used to it. But on the GX you can unlock the center diff and render it a non-issue.
r2m
Richard
Per your example above, you would never unlock during a steep descent until you were in a flat non-critical section of the trail.
Even long straight steep descents should use either/and/or DAC and 4Lo for best control. Last thing you want is to start sliding down a very steep section and have your back end start swinging around, or slide into a waterfall step with a bad line of attack, or many other scenarios.
I used 4LO, CDL, and DAC for the first time last month and thought I turned my transmission/diffs/TC into marbles. I let it ride a bit longer and realized it was actuating the ABS system. I was on a wet, rutted dirt road and it was engaging the brakes hard enough to cause the truck to slide in the almost-mud. Granted, I'm on stock wheels and tires, so maybe that was a bigger factor in my grip problem, but I was able to significantly reduce the sliding by using low gears and working the brake pedal myself, though maybe I was heading towards over-working the brakes. I'll give DAC another shot sometime. I should also have new wheels and tires by Jan/Feb, I think.
I really wish I could get CC on my 2021. Sounds like a much better feature.
- Thread starter
- #33
So, I took the truck to Anza-Borrego to test everything out.
It went amazingly well. My GX460 is bone stock, but even so, it is a pretty darn impressive off-road vehicle.
I went down and up Diablo Dropoff multiple times in 4LO, and with the diff locked, it was almost too easy. Just for fun, on one of the passes, I used Crawl Control and was amazed at how smooth and controlled it was.
Elsewhere in the park, I had to use crawl control to climb a very short but steep incline, and I couldn't believe how easily it did it. I felt as if I was just scratching the surface of what this truck could do.
The only thing this truck needs is a few extra inches of ground clearance. That would have made traversing some of the rock gardens easier. Other than that, this thing is gold.
It went amazingly well. My GX460 is bone stock, but even so, it is a pretty darn impressive off-road vehicle.
I went down and up Diablo Dropoff multiple times in 4LO, and with the diff locked, it was almost too easy. Just for fun, on one of the passes, I used Crawl Control and was amazed at how smooth and controlled it was.
Elsewhere in the park, I had to use crawl control to climb a very short but steep incline, and I couldn't believe how easily it did it. I felt as if I was just scratching the surface of what this truck could do.
The only thing this truck needs is a few extra inches of ground clearance. That would have made traversing some of the rock gardens easier. Other than that, this thing is gold.
r2m
Richard
Aside from a wee bit more ground clearance, trimming the front and rear bumpers will help a lot with approach and departure angles!
