4x4 not working

[dagwoods4x4]

I have a 94 Jimmy SLT with lever engaged 4 wheel drive. When I put the lever into 4 high I can feel it engage,but the front wheels are not being powered.
I have looked under the vehicle, and nothing looks wrong. Anyone have any ideas before I spend big bucks at a service center?????? Also 4 Low is not working either.

[Sparky2263]

Make sure the front driveshaft is indeed sending power to the front axle (turning).

Most likely cause is a vacuum leak in the front axle vacuum actuator system. The actuator is under the battery and the vacuum switch is located on top of the transfer case. The vacuum source is from the intake manifold at a vacuum tee check valve.

[dagwoods4x4]

hey,

thanks for the info. i'll let you know what i find.

[1993blazerlt]

the vacuum on thoes tent to go bad a good solution is to replace it with a cable operated system. I just did this on my friends 89 it also adds another gear when this is done. With the cable conversion you have 2 low avialble

[j894]

When in 2wd reach under the drivers side and see if your
able to rotate the front drive shaft. Then switch it into 4x4,
reach under there again, it shouldn't move.

If that works check all the vaccum lines going to the T-case, for
breakage/cracks. I had an exhaust leak or something that was causing my
vaccum lines to dry out & crack. I think I replaced them 3 times in the past
couple weeks trying to prepare it for winter. I finally wrapped them with
insulated foil tape, and they seem to be alright. The leak wasnt worth fixing.

[dagwoods4x4]

I think i'm going to use the cable conversion unit. the vacuum deal is just stupid.
does anyone know the maker of the cable unit??????

[Sparky2263]

http://www.eastcoastoffroad.com/posi/

[T Man]

Wow, only 165 to put one of those on the old burban. hmmmmmm

[dagwoods4x4]

hey t-man,
how do you like the cable conversion, and does it work well??????????
the cost may determine if I use the conversion or just fix the vacuum system.

[Sparky2263]

The S is $113. T-Mans is an electric solenoid, that's why his is more expensive. Different kit.

[T Man]

Ya, I havent done mine yet, but 2lo??? How kickass would that be, talk about a torque MONSTER! 454, 3/4ton 4wd