4x4 issue...

What do you mean by 'brakes almost give out'? :thinking:

I mean they lock up or at least it feels that way. I have pulled the emergency brake before to stop.

is there a lot of pressure on the brake pedal?

Yes. The pedal feels as though it would take 1000 pounds to press it.

Also, the sound it makes seems to me as though it may have something to do with abs but I know squat about this part of the truck.

ABS is what I suspected, even before you mentioned the sound ... :thinking:

Do you have the traction control / etc. ?

The 4WD engagement wiring doesn't interact directly with the ABS circuits, but the traction control stuff does. The 4WD circuit interacts with the Skid Control ECU (which uses the ABS to manage the wheels).

I'm wondering if there's a hydraulic fault (like a pinched line) or an electrical fault that's causing the ABS to go nuts ... If it's the ABS, I'd just about bet the Skid Control ECU is involved somehow.

I have the off-road package with rear differential lock but i have never engaged it actually. I don't have actual traction control in the truest sense of the word though. Thanks for the comments. I've made an appointment for service tomorrow. I hope it doesn't cost an arm and a leg!!

The guy at the dealership (mechanic) told me the abs was kicking in and this feeling was normal. I don't like it but he drove it and rode with me and felt the pressure and heard the noise and still said it was the abs doing it's thing. I believe him since he told me he was just happy to not be fixing gas pedals on recall. Thanks for the help.