4x4 Question

[masterpete]

I lifted up my 99 explorer 4 door today on jackstands. All wheels off the ground. I put it in drive and all 4 tires spun even though its set to auto on the 4wd button. Are they suppose to do that or is there something wrong?

 

[codeman200]

i think thats supposed to happen because with the way the 4wd system works, if one wheel slips, it will transfer the power from that wheel to a wheel with traction. now in your case, all the wheels are off the ground, and you put it in drive. the computer senses that the rear wheels are moving, but not the front wheels, which on land, means that your stuck and your not moving, so the computer transfers the power from the rear wheels and sends it to the fron wheels so all 4 wheels move at the same pace.

 

[masterpete]

Thats what I was thinking, but I had to make sure. Another thing is that wheni let off the brake while on jackstands without even pressing the gas it would go up to about 25 mph on its own. Theres gotta be something wrong there or no?

 

[codeman200]

no, i think thats normal too. the idle speed is enough to spin the wheels, but when the wheels are on the ground, the weight of the xplorer is too much for the idle speed to turn the wheels

 

[Rottie]

I agree with Codeman. Sounds like you're all OK.

 

[gijoecam]

Indeed, everything sounds normal to me.

 

[masterpete]

Ok that sounds good guys, I've never had a 4x4 and I just wanted to make sure. Thanks for your help guys.