Hi Guys,
want to know if you guys feel the samething I do. When its raining and its really coming down I like to put the truck into auto 4WD. Sometimes when accelerating You can feel the front diff. (20-40mph) you can feel the auto 4WD. Steering wheel does not vibrate but you can just feel it in the truck. Then it goes away ones your up to highway speed. I wanted to know if you guys feel that too.

Thanks

 

In auto 4wd, if the rears slip, the fronts grab. Yes, you should be able to feel it.

 

the rear is not slipping this is under normal driving.

 

You may not feel the rear slop, but it is. That's why the front is engaging, also the rear power is cut. This is the point of the Auto 4wd, as on tire slips, power it cut and given to another tire.

The system in these RAMs are not as elegant as other, so this is why you are feeling it happen.

 

Gtivr6,

4WD auto should be power to the rear wheels only unless some type of traction issue is detected. From the manual:

4WD AUTO
Four-Wheel Drive Auto Range - This range sends power
to the rear wheels. The four–wheel drive system will be
automatically engaged when the vehicle senses a loss of
traction. Additional traction for varying road conditions.

 

I like the fact that I can feel it engaging...It helps me to know that I could be pushing the limits of the road. Especially on ice and snow. If it did it seamlessly it would be harder to tell if its engaging, meaning you really would not know the conditions as much.

We also have to remember that when we are on 4wd auto, all the linkages are engaged and the front drive is turning. I don't know how they do it, but I suspect they use some sort of planetary gearing in the transfer case to put more power towards the front. As far as pulling power off the back, I think it uses the ABS system for that, but there could be the same type of system for pulling the power off.

If I remember right I read somewhere that on 4wd auto you are running on a much lower power ratio. I think it was something like a 90%-10%, when its slipping it goes into a 60-40 or something like that. I don't think it was a full 50% ratio.

 

From what I can tell the 4x4 auto is very similar to Suburu's AWD system... VS the 4x4 Lock is a true 4x4 system...