All wheel drive

#1

I have an AWD SUV and have no trouble on snow driving uphill, or starting out on a snow covered hill, but if I attempt to back up the same hill my wheels usually spin. Is this because of the gearing ratio in reverse, or does AWD only work in forward gears?

#2

Not all AWD systems are the same, and without knowing what you are driving it’s really hard to say why this happens. Reverse is geared lower, and may be partially responsible, but I think it’s more than that.

In theory, AWD should work going forward or reverse, but different systems allocate drive power or torque depending on different conditions.

Which wheels spin when you try to back up a hill? Front or rear? What kind of SUV do you drive?

Some systems don’t activate the rear drive until they detect wheel spin at the front, others drive both axles all the time. There is a lot of variation in AWD.

#3

What kind of SUV is it?

#4

More details about your vehicle would help…year, make, tires, drive train options etc.

#5

I agree with the others. I have to relay an experience I had this morning. I was driving up a hill and passed a small SUV. The SUV was stopped dead in the next lane with both driver’s side wheels spinning. My FWD car was having no problems. I suspect the SUV did not have winter tyres and I did.

#6

If I had to guess, I would say it is because your SUV is equipped with traction control and it doesn’t work in reverse.

#7

You remind me of 15 years ago while clearing the land for my house in the winter on a 2 mile dirt road, I had to drive ahead and sand the road for the other workers who had a 4 wheel drive truck and summer tires. I had a 2 wheel drive truck with studded snows and 5oo lbs of sand. Nothing beats appropriate tires.

#8

That is my theory also.

In addition, it is unlikely that the OP has equipped his vehicle with winter tires. Even though I have AWD, traction control, ABS, and vehicle stability control, I won’t drive in severe winter conditions without a set of 4 winter tires.

If the OP is not using winter tires, he will never experience the full capabilities of his AWD system.

#9

The SUV is a 2004 Mitsubishi Endeavor. The tires are all weather, but I don’t see how the tires effect the situation, they are the same whether in forward, or reverse. I believe it is the front wheels that spin. The transmission is a four speed automatic with sport shift option.

#10

If traction control only works in forward gears, having winter tires would make it easier to move the vehicle in reverse in low traction conditions. AWD won’t help you if your tires can’t get any traction…well it might, but it will be less effective.

Does your vehicle have traction control? What does the owner’s manual say? Does it say it works in reverse?

#11

Here goes my hypothesis. When you drive up hill, your center of gravity shifts down hill . That would be a plus going forward as that shift is somewhat balanced out by the weight in the front. If you back up hill, you now have both your engine and weight bias down hill. If your awd is capable of a 90-10 split for example, you still have 10% or more bias over drive wheels with no weight to speak of and a center of gravity shift to opposite axle down hill…the rear wheels I feel would tend to spin more regardless.
I do believe my Rav would do the same thing if the situation were aggravated by not having tires with enough traction…all season instead of winter. So better tires I believe would mitigate but not eliminate the tendency.
All 4 and awd trucks and cars I have driven were always a little worse backing up hills (unless bed was loaded)…Front drive cars improved in their up hill traction backing up the hill.