i was out at some trails yesterday and my engine started vibrating really bad when i was climbing, could this be a loose electric fan blade, or a bad fan clutch, it also does this when the heater or AC is on.
BTW it is a 96 with a inline 6 aw4 tranny, idk if that helps but i put it anyways!

 

The two things that come on when you run the ac is electric fan and ac comp,check both and see if it could be the problem.

 

the PO had the ac compressor replace a week b4 i purchased it, i saw the receipts. i checked the electric fan and it wobbles back and forth, is this bad? and i read somewhere that if it is too easy to move the mechanical fan side to side there is a bad fan clutch?? i can spin mine with the flick of a finger.

 

Being able to move your mechanical fan clutch with your finger does not mean it is bad,warm up your engine and see if it is harder to spin thin.

 

okay thanks, i thought i remembered reading that somewhere.

 

My 96 XJ did the same thing.There are 2 plastic tabs on the bottom of the electric fan that slide into the radiator . 1 of those or both are broken or cracked . It causes the whole Jeep to vibrate. You have to replace the fan to fix it. Mine still does it. I have it hooked to a switch so I can use it full time when offroading. Only does it when on.