1991 Jeep Cherokee 4 wheel drive

1991 JEEP CHEROKEE
317,078 MILES • 6 CYL • 4WD • AUTOMATIC
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JOSH MONROE
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my 4 wheel drive does not work, i can put it in 4wh and 4wl and drive shaft turns but it doesent lock it into the axle, i look inside the diff and there is nothing wrong with the pinin or anything else the axle is good, i looked at the shift fork and thats good to, i have replace my transfer case, i changed all the oli.. i dont know what else to do
Jan 5, 2009 at 12:51 PM
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JACOBANDNICKOLAS
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Hi:
There is a vacuum control block on the axle. Is it getting vacuum?

Joe
Jan 6, 2009 at 4:14 PM
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JOSH MONROE
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yes its getting vacuum to it, but both the vacuum lines are sucking in air is that bad or good? see i asked so many people about the vacuum lines but and noboudy knows
Jan 7, 2009 at 11:48 AM
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JACOBANDNICKOLAS
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  • 110,175 POSTS
Hi:
I believe you should get vacuum to one at a time based on the shifter selection. Try this test. Disconnect one line and plug it with a screw or colf tee. Se if the 4wd works. If not, try the other hose to see if that helps. If it does, there is a vacuum solenoid that is on the top of the transfer case that may be the problem.

Let me know what happens.

Joe
Jan 7, 2009 at 1:41 PM
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JOSH MONROE
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ok this is what i did, the two vacuum lines that come up to the engine compartment i put them on the same vacuum line so now they both suck in air, when i hook up both vacuum lines to the shift motor and put it in 4wd it doesent do anything but if i take one of the vacuum lines off the shift motor. it will lock in 4wd but if i try to take it out of 4wd and one of the vacuum line is still in the same hole it wont unlock the axle. i took the shift motor out and hook it back up to the vacuum lines so i can see what it was doing it did the same thing. nothing happen untill i unhook one of the lines then it moved
Jan 7, 2009 at 3:30 PM