4doogie

hey guys, my 4x4 is locked on, do you guys know what it is. It's in two wheel but the hubs are locks and the drive shaft is spinning. Im guessing its the vac. pump is eather bad or i have a vac leak somewhere thats the only thing i can think of. Can anyone tell me where to test or look at of tell me where the lines run so i can check them? if anyone has a diagram of how the vac system works that would be great, thanks for the help guys.

torquefan

Remove the 2-line vacuum connector from the front axle disconnect. Start the truck and let it idle, then climb under it. (make sure it can't move) In 4WD, there should be vacuum on one line (the black one I think) and the other should vent. Now switch the stick to 2WD. There should be vacuum at the second line (the red one I think) and the opposite one should vent. (Vacuum should be 15" or more.) If this is all correct, I would focus my testing on the vacuum disconnect components. (vacuum motor, fork, sliding collar, shafts etc. If the vacuum is not correct, I would look for a vacuum leak, faulty vacuum switch (on top of the t/case), or plugged line- depending on what you actually see.

2stroke

the lines will usually brake where the run ove the trans up to the motor. im sure it has a vaccum leak.

MikeR

The most common problem I see here is somehow oil contamination gets on the rubber vacuum connections at the axle and near the transfer case, the rubber swells up and leak bad or just fall off. Crawl under the rig, you can't miss the lines, and take a look.