I have a 1993 S-15 Jimmy 4 Door. I am trying to figure out why my 4x4 won't work. Please help me! When I push the button to 4hi or 4low I can hear the tranfercase moving into the gears. With that said, when the button shows that it is in 4x4 mode the drive shaft from the trasfercase to the front diff. is engaged but the axel shafts from the front diff. to the wheels do not spin. I jacked up the jimmy to test and look at this. I'm not positive on how the vacuum system works on the 4x4 though. Thanks for your help!

 

There is a vacuum ball on the passenger side, probably under your battery. Make sure all the lines leading up to that are ok. That vacuum actuator can also rupture. Another thing to check would be that the actuator isn't filled with ATF. When the front seal of the transfer case leaks (between the transmission and transfer case) and the case fills up, fluid will start to come out of the front driveshaft seal and make its way up to the vacuum lines and actuator. The actuator and lines may be filled with ATF

 

the vacuum line runs from the intake to the tcase then back up to the acuator under the battery tray there is a t in the line buy the battery a selenoid there with a wire hooked up to it if u dont have vaccume to the acuator it wont pull the cable to lock in one of the axle shafts hope this helps

 

Lastnight I finally got around to looking at the vacuum lines. I found that the vacuum plug to the transfer case did not fully set onto the case. there is about a 1/8" gap, but the plug is being set on all the tubes coming out of the case so i'm thinking that it might not be the original lines. There are three lines comming from that connection. One of them gets split into a "Y". It almost looks as if all the lines go up into the engine compartment but I'm not positive. When I pull that vacuum plug off from the transfer case, if the lines are full of fluid, will the fluid just run out? Or does it have to be forced out? Are there any vacuum lines that run to the front differentual? Thanks!

 

You should be able to find the NV231/NV233 vacuum diagram in one of the 4wd threads in the Tech Article (DIY) section. That should help.

As far as how to clean the lines, I wouldn't rely on it just draining out. If you have fluid in your lines, hopefully it didn't get up into the HVAC system.

 

Well this weekend I messed with it a little and my vacuum lines are all messed up! For some reason there is no vacuum to the actuator. So now I'm worndering if I can just clamp together the actuator so that the front differentual is always locked in? Will this hurt anything?