Crawl Control ? what's up with all the clatter and grinding?

On my new TRD DCOR (2020) I decided to see what the crawl control is/does.
I re-read the manual to be sure I was "by-the-book" and went to a large abandoned parking area.
It's spring break, so the local school sufficed. Placed the truck in 4H on the way there, stopped, shifted to Neutral, placed in 4L. Put trans into drive, made sure all idiot dash lights illuminated. i then braked the truck to a stop and pushed the crawl control button. I also had the dial rotated to the #2 spot (#1 being slowest setting). HOLY COW! the front end sounded like it was going through a grinder. Clatter- Chatter- grind. Antilock brakes chattering or maybe traction control chattering. But traction control is suppose to disengage. My brake pedal was vibrating/pulsating like a woman's "happy toy". I stopped the vehicle which stopped the inability of diff to attempt to engage and stopped the grinding. I then turned off the crawl setting and let the truck inch slowly forward in 4L. No abbynormal sounds from front with crawl in Off setting . I decided to attempt this again but while truck was moving slowly forward. I pushed the button to activate and again, it sounded as though parts just were NOT meshing. However, I did apply brakes, and while gritting my teeth because of the sounds coming from front, I was able to wait it out ,slowly, very slowly , moving forward the gringing ceased. The anti lock brakes were also chattering as the gears attempted to engage. After a few feet of agony, the truck appeared to settle in and the self destructing sounds stopped. On another note, This was on completely level pavement while moving in a straight line.
Ok, now that I've described my first attempt with the crawl control,What am I doing incorrect?
surely this isnt a normal action!

 

Normal

 

It's working exactly like it's supposed to

 

Engaging crawl control on pavement is probably sub optimal.

 

You didn't set the hand brake first then release before pushing the crawl control button?

Oh man, that's the self destruct sequence. Sorry, there is nothing you can do

 

You say you put it in 4HI on your way there, we're you on pavement and turning while in 4 HI?

 

Toyota corporate says this is normal.

*turns and whispers to offstage* Did I do that right?

 

That was your 1st mistake. 4X4 should never be engaged on dry hard surfaces. Only on surfaces where traction is poor. You're going to break expensive drive train components.

At the minimum you need to do this in a loose gravel road where the wheels can spin in the gravel without putting the drivetrain in a bind.

 

I couldn't read all that, but the vibration and noise is the ABS system working the brakes, they all do it

 

Now pick up all the peices you broke off your truck driving on dry level pavement in 4wheel. Take it to a gravel area or sandy area and try again. Yes some of those noises are normal, I am betting some are not because of binding. Never engage 4x4 on dry high traction surfaces like pavement.

 

Re-re-read your manual.

 

If he was going straight while using crawl control, like he said, it's fine.

 

I applaud you going through the manual and trying to do it by the book, seriously, that's more than most will do, they just hop on here and ask questions like "why does my reverse camera only come on in reverse?"

Now, with that said, you missed the line about where you don't use 4 wheel drive. The Achilles heel to a truck is dry pavement. The power (energy from the engine) is gonna go somewhere and you'll find the weakest part of the driveline if the tires can't rotate and move the truck forward or when in 4wd, slip to release the difference between each due to the radius of the turns. An open differential in 2 wheel drive makes that a non-issue. Your transfer case does not have a differential in it (many do nowadays, they are called full-time 4wd or all wheel drive) so your front and rear axles get the same rotation and power. TRD OR and Pros have lockers in the rear to stop the differential from letting the wheels rotate at different rates, all are stock open fronts. That's where the binding is coming from.

And the bad noises (if you turned the wheel) are moans and groans from the binding but if not, it was your ABS pump working it's butt off trying to keep the wheel speed really low. In use, like sand, it would assume the fastest rotating wheel is spinning and act accordingly. Crawl control a neat trick for people new to offroad. Its often a punch line but we all learned somewhere and those who talk the loudest were probably the ones that had to pay to get pulled out.

Go find some dirt and enjoy your truck!

 

Everytime I hear crawl control working I go...

 

Crawl control always sounds like your truck is about to grenade. It is the ABS system doing its thing. Dry pavement probably did not help as there is no slippage and things want to bind, so the ABS system gets more frantic. Did you wreck anything? No. Just not a good practice long term not to do this stuff on pavement. The OR ABS system is completely different than on the other models.

 

4 Wheeling in a parking lot?

 

Using crawl control when crawl control is not required is a fools errand. The system struggles when asked to crawl on something that you could drive in 2WD.

If you ever need it, in conditions that warrant it, (steep ascents and descents) it works great.

 

I don't have crawl control, but first time I used trac lock to get out of a big hole, the sound scared me at first. Sounded like a machine gun firing, but out she came.

 

I have shared this a couple times before, but it is the best demo of the system on YouTube:

https://m.youtube.com/watch?v=NZ-Cq_b_UbI

 

I used crawl for the first time a couple days ago in the back pasture just to see what it was all about and don't think I'll push that button again. In the lower two settings the truck bucked and lunged like crazy. Top 3 setting were smoother, just the abs and other funky noises that come with crawl mode I guess.