Crawl Control Diff Noise

My 2016 Taco makes the most God-awful noise when I try to activate it in crawl control. I read on another thread this is normal, but I’m making sure because this sounds like a bat out of hell in the diff. I have a video I can upload

 

https://www.toyotaknoxville.com/blogs/1021/toyota-of-knoxville-what-is-crawl-control/

Like this? At 2:50

 

I can kind of hear it in the vid, but it’s super loud inside the cab. Like this https://youtu.be/dcmH0OARym4

 

Normal. You can’t use crawl control in lowest speed on flat ground. Toyota doesn’t do a good job of explaining this.

 

I can’t really tell what’s going on in that video, but the sound reminds me of the normal ABS brake sound of ATRAC et al when the wheels are spinning at different speeds.

 

Wha? Do you mean specifically crawl control or are you referring to all of the 4lo traction modes? I can’t think of any reason that any of them could not be used on flat ground. I use ATRAC all the time on flat ground. Are you perhaps thinking of turning sharply in 4wd on a high traction surface? That is well known to be a bad idea.

 

Specifically crawl control. The system is not designed to work on flat ground with no resistance. When you need it, it will be fine.

 

I was told by another person that has a TRD Off Road, and he said that I need to see a dealer. But when I turned up the speed the diff sound went away. So it’s relieving to hear from y’all it needs an off road environment and that it’s normal.

 

Welcome to the world of controls!

Yes, that's normal. It's just your braking system pressurizing fluid and firing solenoids to maintain a set point.

 

Hm, interesting. I still don’t understand why flat ground would cause a problem. I have a 6MT so I can’t go try it myself.

 

It overwhelms the braking. It can’t feather the throttle low enough and modulated the brakes fine enough, when the trucks tires have zero resistance. There’s nothing for the brakes to hold back (so they don’t slip at all) and any movement of the throttle is too much.

crawl control is designed to work when you need it, not at the mall, though Toyota really doesn’t explain this very well, hence all these endless threads with guys complaining about crawl control making sounds on flat pavement, etc.

 

So it thinks it’s going too fast and is trying to slow down using the ABS brakes? I guess that makes sense and would explain why the problem goes away when the speed is adjusted higher as reported in the thread.

 

Crawl control works by applying the abs system and the throttle concurrently. It isn’t calibrated for zero resistance. Toyota alludes to this in the manual, but doesn’t articulate it well.

Lowest setting of Crawl Control is for like a 45 degree incline or decline. Even the fastest setting struggles to be smooth on flat ground. It’s just not the intention.

it’s a great and powerful system when you need it. On extremely steep stuff it does add traction and confidence, as it never releases the brakes, and the truck never slips or gathers momentum, which is nice when you are facing downhill.

However they market it in North America as something to help you get unstuck (I doesn’t do that.....stuck is stuck) or something for sand driving. It’s really not either of those things. It’s more like a safety feature for sketchy ascents and descents in my experience.

 

Does it not work well if situations where you are driving mostly on flat ground but driving over large rocks where a constant slow speed is otherwise hard to maintain (especially with a MT)? I sometimes struggle to keep the truck crawling forward smoothly as the wheels are ascending and descending large rocks. I guess that’s what I thought it was intended for.

 

Toyota Canada did an OK job with this.

They specifically say, at the 2 minute mark, that speed setting 1 is for “downhill moguls and downhill gravel”, and the system is for “severe terrain”. No mention of flat ground at all.

https://m.youtube.com/watch?v=65vbsUXPWck

 

It does an OK job of that at the higher speed settings. It makes a racket (as all four brakes are constantly pulsing on and off), however, I find the system is most useful when the type terrain you are facing is consistent, so you can select a speed that doesn’t surge when you hit easy spots.

It’s a good system, that just uses the existing ECU and ABS system, so doesn’t cost Toyota a lot to implement, but it doesn’t work miracles. I’ve truly felt I needed it only a couple times. Mainly on scary downhills.