I got my MMH with what is claimed to be 4wd. Does anyone know how this works? I dont have any switch, button or dial to engage the 4wd mode. Is it automatic? and if it is is there any indication at all that it's on ?

 

Normally it's an extra shifter next to your drive,park shifter for a 4WD vehicle, there are some systems that only come on when rear slipage occurs suchs as the Honda's CRV (real time drive). So a 4WD is really a 2WD drive but can engage all 4 wheels if needed. Most systems, the driver engages the system manually.

I assume your MMH has something similar to the CRV.

Do not confuse a 4WD system with an AWD system. They are different in that the power transfer to any individual wheel can be manged better (way better) in an AWD system. Where as the 4WD system, the power is divided equally which isn't always optimal.

 

Using generally accepted industry terms, it's technically AWD. But they may label it as they wish, and Ford likes to use the term 4WD when they're dealing with anything that could be described as a "truck". If they used the same system on a car, they'd probably call it AWD.

It's FWD until one of the front wheels slips. That slippage causes the center coupling to lock, engaging the rear drive shaft. It's automatic. There's no light to indicate you're in FWD or AWD. There's no limited slip on either the front or rear drive.

 

I'm pretty sure the FEH/MMH has an "intelligent 4wd" system which is activated when the computer senses wheel slip (probably via the ABS sensors in the front wheels). There should be a light on the left side of the instrument cluster that says 4x4 (I think it's three up from the bottom).

Check the owners manual as I'm sure it's listed there along with a short description of how the 4wd system functions.

I also believe there is an XGauge you can put in for the SGII that will tell you if the 4wd is active (if you have an updated SG with XGauge capability).

 

I don't think that there is any visual indication that the 4x4 system s active.

 

it is an part-time, automatic AWD. It is FWD until traction slip is detected, then it shifts torque to the rear axle as needed (up to 50% I think).

I think the generally accepted distinction between 4WD and AWD is that 4WD allows you to select a "low" mode, which is ideal for off road conditions. Other than that, most AWD and 4WD systems today are essentially identical for onroad driving; the differences are seen in whether your drive system is full time or part time.

 

I would disagree in that I don't believe a 4WD system allows a variable percentage of power to go to a set of wheels.

Most AWD system allow a variable amount of power to go front or rear wheels and in some systems from side to side were all the power can go to a single wheel. Good luck finding that in a 4WD system.

Essentially a 4WD system is a very crude AWD system once engaged.

 

Our FEH is AWD. I witnessed this yesterday. We had big snow over the weekend and live on a steep road. I watched Natalie pull out of the driveway and up the hill. she was slipping on the ice and the wheels were moving at different speeds to get traction. Our 4WD Dakota does not behave like that.

 

Sounds like you haven't read your manual yet.

 

That just means the fixed amount of power going to the rear wheels is less than 50%. It's still a 4WD system.