switching to 4 wheel drive does not work

Don't get me wrong here you might be doing this right but if you are trying to get in 4 LO it must be in neutral or it will grind until it's locked in.

Tell me does this have the select trac or quadra trac system? If you don't know just tell me what it say's inside like does it say part time, full time low and 2wd or ? Get back to me so I can try to help.

it has a lever next to the gear shifter. it goes 2H, 4H, N, 4L. the rest of the time it stays in 2H, and when i switch it to 4H a bad grinding sound comes from the front axle area when i start to accelerate.

Ok what need to be done now is check the vacuum switch. Now on the transfer case there is a vacuum switch with 4 vacuum hoses connected to it. Now use the pic below to do the following test. In 2wd use a vacuum pump to get 15 inches of vacuum to L. Now you should have vacuum to M. Now switch to 4x4 and apply vacuum to L and you should have vacuum to N. If any of this fails then the switch is bad. Let me know what you find and we will check the front differectial actuator next.

The people before me took out the driveshaft to make it a 2 wheel drive to save on gas. I put the driveshaft back in after purchasing the jeep and the front axle is spinning but the wheels are not.

See my profile...........I'm guessing you have had him up on 4 jackstands to come to this conclusion.....See my profile......newer stuff, especially all wheel drive etc. is not my cup of tea.......Older REAL JEEPS were always locked in (axle to wheel) on the front end.......someone came up w/ idea of MANUAL LOCKING HUBS (to save gas + wear on frt. diff. + components).......Then rocket scientists came up w/ auto unlocking hubs, you go in reverse 20 feet to unlock......Know that '70s quadratrac MUST stay in 4WD always, because transfer case sorta acts like a diff. from frt. axle to rear axle (man. hubs installed [by 2 dumb soldiers in 1984] make it spin axles, not coupled to wheels any more, JEEP NO MOVE AT ALL w/ quadratrac (ALL WHEELS MUST GET POWER), this is where I start getting lost w/ new stuff) LISTEN, SEE IF THIS MAKES SENSE....If I manually lock in my '77 CJ5 (STD. DRIVETRAIN) frt. wheels, I can now shift into 4WD w/ transfer case, If I unlock both frt. wheels, I'm still in 4WD, transfer case is still powering axle....but frt. wheels don't pull, driveshaft spins, one or both axles turn, wheels FREEWHEEL.......Heres the KICKER......If I locked in drivers side wheel and BUDDY THOUGHT he locked in pass side....its really not locked in (I'M NOT IN 3WD!!!)...........DRIVESHAFT and ONE AXLE TURNS BUT NEITHER WHEEL TURNS under power (still freewheeling) because diff. transfers power to unlocked axle (as is that wheel was spinning in a hole) ..................MAYBE your hub is not locking in on one side automatically (if your system works like this)......Maybe jammed, worn parts, broke parts.....or you haven"t been in 4X4 as often as maint. schedule recommends to keep it all lubed up............Just some thoughts.....keep me updated.......Love, Turddog (Got manual locking hubs on both of my jeeps (std. Drive trains)

I own a 1991 Jeep Cherokee 4.0 with 5 speed manual and 4 wheel drive. When I goto engage my 4 wheel drive neither the hi or low will engage. nothing happens. The rear tires still spin but the front don't engage. Do you have any ideas, suggestions, or ramblings that might help?

[quote:704028dcd1="davids1794"]I own a 1991 Jeep Cherokee 4.0 with 5 speed manual and 4 wheel drive. When I goto engage my 4 wheel drive neither the hi or low will engage. nothing happens. The rear tires still spin but the front don't engage. Do you have any ideas, suggestions, or ramblings that might help?[/quote:704028dcd1]

Could be an internal problem with the transfer case.

Is there anything I can do to check that? In regards to the transfer case?

[quote:246ee6f8b2="davids1794"]Is there anything I can do to check that? In regards to the transfer case?[/quote:246ee6f8b2]

Check all connections on it-could be a transfer case control module or a switch/servo

ok thank you I will give that a try.

2001 grand cherokee lorado6 cylinder
only works in 2 wheel drive
no sensors indicating a problem
when shifted into 4 low it will not activate
what are causes for this?

Check the linkage to the transfer case.

"I have a 91 jeep Cherokee, and the four wheel drive is not working. I believe it is the actuator in the front axel. I have vacume to the actuator. Is there suppose to be vacume on both lines going to the actuator? I currently do not have that. the frotn drive axel turns but the front wheels will not engage.

Shift to 2WD position. Locate vacuum switch on front of transfer case. Apply 15 in. Hg vacuum to "L". See Fig. 1. Vacuum should be present at "M". Connect a vacuum gauge to "N". Shift to 4WD position. Apply
vacuum to "L". Vacuum should be present at "N". If switch fails any test, replace switch. pic included