Honda Ridgeline Stuck on Hill

[Klink]

Thats a good picture and I would not have a problem doing that with my truck. Throw some mud in there and get those tires to spin and watch what happens. I am very confident that most front wheel vehicles can climb a hill like that. If you can get your tires spinning then hit the VTM-4 lock and turn off VSA. This would represent a real situation of getting stuck like I did, twice. I have no doubt that my truck can climb hills but when you are not prepared to get stuck, follow the owners man. and see what happens. For some reason I think if you can prepare for getting stuck the results will be different.

When you hooked up the F150 were you already in VTM-4 lock? or did you try to put it on mid pull? I was not prepared to get stuck and did not anticipate needing the VTM-4 lock so I did not turn it on before I got stuck.

[Whaleya]

One question is with the locking diff.

The Ridgeline's rear diff doesn't use a "normal" mechanical lock (like Toyota or ARB), rather it is a clutch pack in the rear diff. (combination center diff and rear diff)

When the rear is locked it is because the clutch pack has been engaged. My question is - at what driveline torque will the engaged clutch pack slip? For example you could have the rear locked but in an extreme difference in tire traction is it possible that the engaged rear diff clutch pack will slip thus only one rear wheel will spin instead of both?

I don't know the answer - on the service manual graphs explaining the AWD and the rear clutch packs Honda(somehow) forgot to put units on the graphs.

As for the reason both rear wheels spin with stability control on I believe that Honda's stability control uses the brakes to help reduce the traction delta on the wheels - thus helping the rear diff by braking the spinning tire, allowing both rear tires to spin with the aid of the locking rear diff.


-W

[MikeT]

Originally Posted by Whaleya

One question is with the locking diff.

The Ridgeline's rear diff doesn't use a "normal" mechanical lock (like Toyota or ARB), rather it is a clutch pack in the rear diff. (combination center diff and rear diff)

When the rear is locked it is because the clutch pack has been engaged. My question is - at what driveline torque will the engaged clutch pack slip? For example you could have the rear locked but in an extreme difference in tire traction is it possible that the engaged rear diff clutch pack will slip thus only one rear wheel will spin instead of both?

I don't know the answer - on the service manual graphs explaining the AWD and the rear clutch packs Honda(somehow) forgot to put units on the graphs.

As for the reason both rear wheels spin with stability control on I believe that Honda's stability control uses the brakes to help reduce the traction delta on the wheels - thus helping the rear diff by braking the spinning tire, allowing both rear tires to spin with the aid of the locking rear diff.


-W

Short of mechanical failure in the clutch packs, when the VTM-4 Lock is engaged, the rear differential will function as a solid rear axle. Both will slip or both will turn. The only way I know of that one will spin and the other not will be with the VTM-4 Lock off or a clutch pack gets overheated or it fails.

[BillyBob58]

Originally Posted by arteegee

It's not a locking rear differential nor was it claimed to be. Vtm-4 Lock sends a certain level of torque to the rear wheels, 60% if memory serves.

Again, bad news. If that is the case, I misunderstood what Honda and or reviewers were telling me about the capabilities of this system. They say to use it "when you are stuck". If you are stuck with your right rear and front tires on a patch of ice or in a mud hole while your left side has good traction, or with your right front and left rear on a patch of ice, and a few other stuck situations I can think of, it is not going to help you to be able to "lock" 70% of engine torque to the rear wheals. All of the power, front and rear, will go to the wheels with no traction.

Ridgeline Owners Club | Variable Torque Management VTM-4 Explanation

Another special feature is a “VTM-4” lock button, located on the instrument panel, which temporarily holds engagement of both rear wheels to aid traction

Now to me, "holds engagement of both rear wheels" certainly at least implies the functional equivalent of a locking rear dif.

So does this, IMO:

On a split-mu (split-friction) grade (different amounts of traction at each wheel), VTM-4 automatically provides sufficient rear-wheel torque to help the vehicle climb steep and slippery terrain such as a steep driveway with patches of snow and ice.

I admit that this might be talking about different amounts of traction between the front and rear wheels, but logically it seems to be talking about differences in right and left. I have had to deal more often with steep drive ways or roads with ice on one side and good traction on the other ( due to sun melting the snow on one side- rt or lt- and the other side being in the shade. Much more often than a dif between front and rear, though it can happen that way also.

Also, there is this from ChrisM, useless info moderator:
Stuck in 20" snow and ice

Are you sure that you had the VTM-4 lock activated? Here is another video of a RL without the VTM-4 lock engaged. The truck will do exactly what you are describing in normal operating mode.

Official Video Thread

The short of it is this. The VTM-4 lock button activates electromagnetic clutches in the rear end of the truck. It is effectively the same thing as a differential lock or positraction. If you were to try to drive your truck in VTM-4 lock mode on dry pavement and turn a tight corner the outside tire would skid because it has to travel farther than the inside tire. VTM-4 lock also sends 70% of the truck's power to the rear wheels.

Also, when I watch the Gary Flint video, at the very end he mentions the "differential lock" during a segment when he gets first the rt front and then the right rear wheels off the ground by a good bit. Zero traction to those wheels, a formula for being stuck ( speaking from personal experience, 1/4" is all it takes). The right front spins pretty vigorously, but the right rear tire ( in the air ) seems to spin almost not at all. If all that was happening was sending a fixed amount of torque to the rear wheels, with no control of whether torque is going left or right, I would expect that right rear wheel to spin like crazy and the left to get no torque and forward motion to probably cease.

But even without any of the info I have read here at this forum, I was under the impression from Honda literature, when I purchased my Pilot in 03 ( and later my RL ) that it had a locking rear dif or something quite close to it in function. That was a major selling point.

So, am I wrong in my impression, and does the RL in fact NOT have some form of rear dif locking ability ( or strong limited slip at least)?

[BillyBob58]

Originally Posted by MikeT

Short of mechanical failure in the clutch packs, when the VTM-4 Lock is engaged, the rear differential will function as a solid rear axle. Both will slip or both will turn. The only way I know of that one will spin and the other not will be with the VTM-4 Lock off or a clutch pack gets overheated or it fails.

Well, I should have read ahead. Mike, I think you have answered my question about whether or not it is ( the equiv of) a "locking" rear dif.

It seems to me that, if the truck is functioning correctly, there should be no case of one rear wheel spinning and one front spinning, with the opposite sides just sitting there getting no power. One front can spin, yes. But not just one rear, if functioning as advertised.

Unless, of course, wheel speed is too high, in which case VTM-4 lock automatically cuts out.

[k757]

If only all of you were at the National Meet, this thread would die immediately as you would have seen what happens with the Ridge and the Tacoma. They started on a 20% grade hill with the right side incapacitated by being on simulated ice (water running over smooth tile)

[BillyBob58]

Originally Posted by k757

If only all of you were at the National Meet, this thread would die immediately as you would have seen what happens with the Ridge and the Tacoma. They started on a 20% grade hill with the right side incapacitated by being on simulated ice (water running over smooth tile)

I would have loved to see that! Please,tell us more! Maybe I can view it in the video link at the bottom of your post? I'll give it a try!

P.S.
I don't find any thing yet in the videos. So fill us in on the results, please! Or maybe you have a link showing the hill climb?

[k757]

Originally Posted by BillyBob58

So fill us in on the results, please! Or maybe you have a link showing the hill climb?

TuttleImages Marysville, OH- powered by SmugMug then click on Ridgeline for a couple listed in there (thanks ridgeln)

ChrisM's writeup of the Factory and TRC, plus additional info from others