I'm not an expert on 4wd, but I know many of you are.


I was driving in 4 low on my lawn (dumping some firewood). I was trying to back up across an incline. The truck started to slide a bit. Ok.
Then it sat spinning and not moving at all. I was somewhat surprised. I took a look and neither driver side (down hill side) wheels were spinning under load. Is that normal? I thought all four wheels lock and spin under load.


TomJV

 

Locking diff or limited slip?

 

Grass. Especially wet grass. Without lockers, if one side loses traction, guess what? Open diff=one wheel wonder. Sends all power to the path of least resistance.

 

If you have an ELD, pull the 4WD **** out to lock the rear axle. If you have an LSD, try feathering the brakes a bit.

 

Yeah that sounds normal unless you have a locker or limited slip. Most 4WD trucks can spin 2 wheels in 4WD under certain conditions. Many times I've had the built in traction control help -spin the tires a bit and the brakes will be applied to spinning wheel and some traction may go to non-spinning wheel.

If you have the rear locker that may have helped -would have essentially been 3 non-spinning wheels at that point.

I miss the front torsen in my raptor, basically made it more of a "real" 4WD vehicle.

 

without electronic locking rear end, you can end up spinning just two tires (one front, one rear) when it gets very slippery. I think 4 low also turns off traction control so the brakes weren't acting to stop the spinning wheel and send power to the other side of the axle.

It's one big reason I'd love for manufacturers to bring back true limited slip differentials. With something like a Torsen (gear driven lsd) it won't wear out and in a worst case scenario you put just a tiny bit of brake pressure on and it'll transfer tons of power and get you going. You can try dragging the brakes a bit and it'll send some power to the other wheel, but it's not guaranteed to help.

 

Thanks for the advice gents. I completely forgot about the elocker. I tried it again and engaged it. The truck performed like a champ.


Still I'm confused about the 4wd. What's the point if it's not really 4wd? My Ridgeline would have done it.


TomJV

 

no it wouldn't. The ridgeline is no more 4wd than a non-locker equipped F150. I had a pilot, same 4wd system, and distinctly remember somebody posting an exact circumstance of driving ridgeline on wet grass and slipping like crazy.

 

4WD has always been what you experienced, you get one front and one rear wheel and you don't get to pick which wheel it will be. That is just how an open differential works, the wheel with the least traction gets the power.
2WD you get one rear wheel under those conditions. Limited slip or a locker can solve it. Systems that use the brakes to apply pressure to the slipping wheel can too.

As for your Ridgeline, the VTM-4 system might have worked there, might not. Had the same thing in a Pilot (really, the Ridgeline is like a cross between an Odyssey and a Pilot with a pseudo truck body). It uses clutch packs to send power to the rear wheels and more clutch packs to distribute power to each side in the rear. It is an AWD system with a front bias. The rear differential is not a traditional differential (it is tiny and they break easily but they work ok for going to the grocery store in the snow).

You probably also had a VTM-4 Lock button that would lock the rear end until you hit 6mph.

There are cases where AWD works better than a traditional 4WD system but in most cases, the components are nowhere near as robust. In the case of the Honda, they require a lot more maintenance too (recommended fluid change interval for the rear 'diff' was 40k).

 

A lot of different threads have discussed this "issue" - not really an issue, just the nature of the beast. As another poster commented a while back on another thread, when you get away from driving on dry pavement, the real operation of our trucks is:

1. 2wd F150 with open rear differential = 1wd
2. 2wd F150 with rear e-locker = 2wd
3. 4wd F150 with open rear differential = 2wd
4. 4wd F150 with rear e-locker = 3wd
5. 4wd F150 with locking front/rear/transfer case = doesn't exist. Have to get something like a Jeep Wranger Rubicon or Ram Power Wagon or MB G-Class or Chevy Colorado ZR2 to get that.