[GCarpJeep]

another question i had with my jeep...

the mechanic i took the jeep to checked the 4wd system and says everything is in order with the vacuum lines. the light on the dash comes on when its put into 4wd drive. the only issue is that, under harder acceleration, the light turns off and comes back on after i let off the gas. again, this is my first jeep so my questions are:

1) is it maybe a vacuum line behind the dash?
2) if the light turns out under acceleration, does this mean that the 4wd is cuttinf off? i would feel some kind of physical "bucking" if this was the case, right?

again, thanks for the help and sorry for being bothersome.

[EABiker]

Mine does that too! There is less vacuum available under acceleration so the transfer case vacuum switch turns off the light and disconnects the front diff. Mine comes back on whenever I lift on the gas also.

[GCarpJeep]

is it supposed to do that?

[starbunas]

Get ready for your vaccum disconnect motor to go south and not work anymore. Pull the vacuum lies off it and look at the motor. Probably starting to get rusty at the connection at the vacuum lines. I changed mine out for about 85 bucks and an hours work. Pretty easy. Most die-hards will
change it out with a more reliable mechanical/ cable deal. I was cheap, and my Jeep is basic transportation. The light on your dash is triggered by this motor.
It really is a piece of cake to switch. I suggest getting a tool to remove the spring clips on the inside. It'll keep you from searching the garage floor when they shoot across the room.

[GCarpJeep]

did you pick that part up at the jeep dealership?

i'm curious about this cuz the mechanic said that he had replaced a vacuum motor. i'd imagine theres more than one suh component in the 4wd system. i have a copy of the work order at home. i'll have to check it out.

btw, where is this part located?

[Dmrennells]

Quadratec or 4WD they are the best sources for parts like this. However I would recommend that you look into a Posi-lock which removes any vacuum process to the 4wd and replaces it with a cable system (much like your accelerator) it is more reliable and gives you 2wd low. The only problem with it is its $200 for the kit and you have to pull a lever to engage the front axel. If you look at the FAQ you can find a write up on how to install a Posi-lock for under $20.

[Burnerman]

Make sure the vacuum line to the tcase switch is teed into the line going to the vacuum resivour under the battery. The resivour should keep the vac fairly constant under acceleration. The Vacuum motor is located on the passenger side of the front axle, it has hoses that run up below your stock jack on the passenger fenderwell.