Downhill and 4WD?

I'm a noob to trucks and 4WD. If I'm going down a hill on a slippery surface, like wet grass or mud, would having the truck in 4WD help to control the descent? Or would it be no different than applying light breaking?

Thanks.

 

4LO will slow you down to a crawl. 4HI will not.

 

The eng. will be holding back on 1 rear wheel, while not in 4WD. With the 4WD engaged the eng. will be holding back equally on one front & one rear wheel. The eng. will hold back a lot more in LO than in HI.

 

It is different, but the difference is a fairly complex vehicle dynamics problem. Assuming all tires have available traction, in 4WD you will get compression braking from the engine at all 4 wheels and in 2WD you will get compression braking at the rear wheels only. Under light braking you also get braking force at all 4 wheels. The difference becomes in how the torque is distributed in each scenario and it's a deep dive analysis depending on available traction, make-up of differentials/transfer case, imbalance of tire diameters, and interaction of the braking system and how that may distribute braking forces via a controller or hardware. The difference you feel will be very small and in most cases something you won't feel at all.

 

Thanks for the responses, guys! Good breakdown, ShimStack.

 

It's better to be in 4lo than to be in 4hi or 2wd and relying on your brakes. A steep/long enough hill using brakes is flirting with disaster, 4lo is the way to go. Brake if necessary but let the low gearing guide you down.

But keep in mind the conditions of the trail and your tires...if you have street tires or bald tread 4lo won't do much if you're sliding.

 

4wd does help braking on slipper surfaces, 4h or 4l.

By engaging the front drive shaft, then allowing the front brakes which are the majority of the breaking power to engage the entire drive line in assisted braking.

This example is on snow and ice, yet mud and wet grass will be the same result. Better breaking in 4wd.