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A FRIEND HAS A 97 TOYOTA TACOMA 6CYL 5SPD 4X4. HIS FRONT AXLE DOES NOT ENGAGE WHEN IN 4WD. I INTENTIONALY GOT HIS TRUCK STUCK IN A SNOWBUNK TO OBSERVE WHAT IS GOING ON. WHEN 4X4 IS ENGAGED, THE FRONT SHAFT THAT DELIVERS POWER FROM THE TRANSFER CASE TO THE FRONT AXLESHAFTS, SPINS. SO THERE IS NO PROBLEM WITH THE T- CASE. HOWEVER, I RESEARCHED AND FOUND THAT THIS TRUCK HAS A VACUM ACTIVATED FRONT LOCKING HUB MECHANISM. THERE ARE NO MANUAL HUBS ON THE TRUCK, NOR PROVISION FOR THEM AS FAR AS I UNDERSTAND. THIS "ADD" LOCKING HUB IT HAS, SEEMS TO BE LOCATED NEXT TO THE FRONT DIFF. IN MY OPINION, THAT IS WHAT FAILS TO ENGAGE HENCE NO POWER TO THE FRONT WHEELS. I DID NOT HEAR A PERTICULAR "HISSSS" NOISE TO THINK THAT THERE IS A VACUM LEAK FROM THE MANIFOLD SUPPLY LINE. ALSO THE "4X4" LIGHT INDICATOR DOES NOT WORK ON THE DASH, WHICH MAKES ME BELIEVE AN ELECTRIC PROBLEM IS INVOLVED CAUSING ALL THIS. I CHECKED THE FUSES, AND DID NOT FIND ANY BAD. HOWEVER THERE ARE A COUPLE RELAYS THERE TOO. HAS ANYONE HAVE HAD ANY EXPERIENCE WITH A SUCH ISSUE ON A SUCH TRUCK? WHAT SHOULD I LOOK AT TO REMEDY THIS? THANK YOU ALL

Hi Sotven,
I had similar issues with a Ford Ranger. I went through several of the vacuum units, all under warrentee, but it seems like a waek system. Not much help to you, but I would check that.
Tim

I don't have much experience with that particular year of truck, but IMS, there is an electric solenoid that controls the vacume to the diff. There is an electrical switch on the side of the tcase (I think) that activates when the shifter is put into 4x4. The switch activates both the dash light, and the electric solenoid. When the solenoid opens, the vacume activates the diaphram on the diff. Its actually a very robust system. If you follow the vacume lines from the diff, they should lead you to the solenoid valve ( I think its up on the fender?). Also, check for broken wires at the tcase. I don't remember if that year is still a mechanical speedo setup, or a VSS. If its a VSS, the wires will go into the tail housing of the tcase, basically right where the speedo cable would go. The shifter switch should be on the side of the tcase, up closer to the shifter. The switch will thread into the tcase and probably have 1 or 2 wires comming out.

Hope this helps. A manual wouldn't hurt either...

THANK YOU FOR THE HELP GUYS. I HAD FORWARDED THE REPLIES TO HIM, BUT HE DECIDED TO SELLTHE TRUCK AS OPPOSED TO BOTHER WITH IT. GO FIGURE LOL THANX AGAIN THOUGH