Hill descent in gnarly conditions makes a grinding noise?

[scoobycarolan]

So last night my buddy and I went out to his land by the Hudson River in upstate NY. We were coming down a steep part of the trail that is mostly fist sized rocks and gravel. So I hit hill descent so I'm not riding the brakes. Once the truck was getting up to speed there would be this grinding sound from the engine until it slowed down. Was that the engine brake??? I was kinda freaked as I've used it a few times before but nothing like this in terms of the condition or noise.

 

[jrmexplorer]

So last night my buddy and I went out to his land by the Hudson River in upstate NY. We were coming down a steep part of the trail that is mostly fist sized rocks and gravel. So I hit hill descent so I'm not riding the brakes. Once the truck was getting up to speed there would be this grinding sound from the engine until it slowed down. Was that the engine brake??? I was kinda freaked as I've used it a few times before but nothing like this in terms of the condition or noise.

According to page 280 of the owner's manual, "Noise from the ABS pump motor may be observed during hill descent control operations. This is a normal characteristic of the ABS and should be no reason for concern."

 

[4pullingGM]

What he said!

 

[scoobycarolan]

Awesome. I did read the manual before we went out but that mustn't have sunk in.

 

[Sgt1411]

Exactly what the engineers told me when I took the Hill Decent mode on the Ford demo hill climb. Worked very well though I was impressed. I had the Ex almost vertical and then it dropped over the other side.

 

[thebrakeman]

What exactly does hill-decent do for you, that you can't do yourself?
Or put another way: What are you doing with your feet that would prevent you from using it for the the brake pedal? Are you simply waiting until the bottom of the hill, then hit the gas? If so, why not just ride the brakes down?

Serious question! Not being a jerk.

 

[Baddecision93]

What exactly does hill-decent do for you, that you can't do yourself?
Or put another way: What are you doing with your feet that would prevent you from using it for the the brake pedal? Are you simply waiting until the bottom of the hill, then hit the gas? If so, why not just ride the brakes down?

Serious question! Not being a jerk.

It's my understanding that hill descent control electronically uses the engine and transmission to slow your rate of descent. There is no additional wear on these components (not noticeably more in the lifetime of the vehicle) to do it this way so it saves you from having to brake all the way down a hill.

You save money on a maintenance part this way (brakes).

Have something to lose when people don't change brakes, brakeman?

 

[sdm9465]

It's my understanding that hill descent control electronically uses the engine and transmission to slow your rate of descent. There is no additional wear on these components (not noticeably more in the lifetime of the vehicle) to do it this way so it saves you from having to brake all the way down a hill.

No, the system also uses the brakes. (There is very little deceleration when downshifting a 2011 as compared to my 2009.) Also, the hill descent mode is only available when you are travelling at 20 MPH or less.

 

[Baddecision93]

No, the system also uses the brakes. (There is very little deceleration when downshifting a 2011 as compared to my 2009.) Also, the hill descent mode is only available when you are travelling at 20 MPH or less.

Ok, I stand corrected....
So I'm with brakeman now (sorry about before, brakeman)....What exactly is the point then?

 

[scoobycarolan]

The point is that the car has a better and faster understanding of the conditions than I do. I was on a pretty steep and badly rutted trail. If I had hammered the brakes I could have lost traction. How am I supposed to go offroading and operate MFT at the same time? Its gotta do some of the work! ;-)

 

[brucekeyes]

Hill Descent & Terrain Management problem

The first time I engaged the hill descent the vehicle made some horrible grinding noises and the vehicle jerked intermittently and uncomfortably off an on.

It continues to make these pretty awful fairly loud noises at the front end on the driver's side in hill descent mode but the jerkiness isn't as bad and left cornering seems worse than right cornering.

Using the Snow/Gravel mode on mostly corners in hills and descents it also makes the noises - that really don't sound right.

It seems to me like the ABS is kicking in under torque/cornering scenarios - as it seems to be engaging against the transmission trying to turn the front wheels at different rates.

To get around this I put it in Mud/Rut mode which I think turns off the ABS as the ABS light comes on but don't experience the problem.

I've had it in twice to the dealer with the first time them saying everything was working normally. The second time took a ride with the mechanic who says that Ford is aware of the issue but are working on a programming fix.

The mechanic also said that the City of Colorado Springs owns a couple of them and takes them up/down Pikes Peak - but they are also having the same issues.

I live up a 2 mile gravel road in Colorado with 6-10% grades climbing/descending about 2K ft regularly - which probably isn't your everyday scenario but its where I experience all of my problems.

Hopefully Ford will come up with a program fix and that's all it is but I also hope there is no long term damage.

Otherwise we really love the vehicle.

Here's a link to a video on YouTube of the noises I'm describing with Hill Descent and Snow Mode engaged.

http://youtu.be/lhIVtimyLlc

 

[1995E]

I went down a very steep hill two times with hill decent control. You would hear the abs firing and the vehicle creeping. I didn't have the guts to let the vehicle do it so I braked and the brakes held on instantly.

Hill Decent Control seems to pre-charge the brakes so it can apply full braking power right when you need it. Pretty neat feature.