1995 jimmy, 4wd doesn't engage. Sounds like it's engaging, but the front wheels don't spin. the guy I bought it off of "supposedly" put some new parts on it. I know it's an easy fix, b

Look under there and see, but I think they (the hub locks) are engaged by vacuum motors.

4X4

On these issue, there are few solved help links for troubleshooting the issue easily.-------

Click the link below: ---

No 4x4 light on dash?

http://repairhelpcenter.blogspot.com/2011/12/no-4x4-light-on-dash.html

-----------

4X4 Truck makes roaring noise in the front end?

http://schematicsdiagram.blogspot.com/2012/01/4x4-truck-makes-roaring-noise-in-front.html

-------------

Car will not go into 4WD high or 4WD low?

http://schematicsdiagram.blogspot.com/2011/12/car-will-not-go-into-4wd-high-or-4wd.html

--------------

No 4x4 light on dash?

http://repairhelpcenter.blogspot.com/2011/12/no-4x4-light-on-dash.html

------------

4 wheel drive system will not disengage?

http://technoanswers.blogspot.com/2012/01/4-wheel-drive-system-will-not-disengage.html

----------

4WD light is flashing and beeping? NO 4WD high?

http://schematicsdiagram.blogspot.in/2012/02/4wd-light-is-flashing-and-beeping-no.html

----------

2002 Jeep Wrangler: 4WD Idiot Light is ON?

http://technoanswers.blogspot.in/2012/06/2002-jeep-wrangler-4wd-idiot-light-is.html

----------

Traction control switch will not engage on 4WD High or Low

http://whoisbyme.blogspot.com/2012/10/traction-control-switch-will-not-engage.html

-----------

4WD light flashing and 4WD will engage after few minutes

http://repairhelpcenter.blogspot.com/2012/10/4wd-light-flashing-and-4wd-will-engage.html

------------

2008 Toyota Tundra: 4x4 Wheel Drive Light is Flashing?

http://technoanswers.blogspot.in/2012/05/2008-toyota-tundra-4x4-wheel-drive.html

----------

4x4 front differential will not engage the axle on ford?

http://technoanswers.blogspot.in/2012/02/4x4-front-differential-will-not-engage.html

-------

4x4 will not engage on Ford F150?

http://technoanswers.blogspot.in/2012/02/4x4-will-not-engage-on-ford-f150.html

-------------

Dodge Ram 4x4 light keeps flashing

4X4 LOW LIGHT IS FLASHING ON DASH

http://technoanswers.blogspot.in/2012/09/dodge-ram-4x4-light-keeps-flashing.html

----------

Ford 4x4 front wheels will not engage?

http://technoanswers.blogspot.in/2012/02/ford-4x4-front-wheels-will-not-engage.html

-------------

These details will help.

Thanks.

on my 2001 jimmy i had the same problem i fixed by changing the actuator on the front diff very simple and inexpensive

It would appear you have a failed CV shaft on your drivers side front. If the axle is jumping around, that means the 4wd is engaged, but the front wheels can't pull because the one axle is just freewheeling. Replace that left axle and you should be good to go. Might want to check the cv boots on the right side axle while you are there.

Try listening to the transfer case try to engage.The vacuum actuater on the firewall above the distributor was not allowing vacuum to the front axle actator. You can put the truck on jackstands (all 4 wheels) and check to see if the front drive shaft engages. If so, then it's probably the vacuum actuator or the axle actuator.

If you can't get 4 high, then you can't get 4 low either. You can get the transfer case to go into 4 low, but unless the front axle is engaged, you will still be in 2 wheel drive. There is a vacuum switch that engages the right front wheel. The left wheel is engaged full time. On earlier models, this vacuum switch is located unerneath the battery tray. It is prone to become disconnected from the vacuum line. Check this and all other vacuum lines that are connected to the 4wd system. The way I test my 4wd Jimmy is to find a dirt or gravel road or parking lot and accelerate hard from a standing start in both 4hi and 4lo. If 4wd is not engaged your back wheels will spin.

It sounds like maybe your auto lockers in your front wheel hubs are not locking. You may be able to get them to lock if while in 4x4 you jab your brake pedal several times, sometimes this will work to get them to engage but even if this works I would advise that you either invest in a good set of manual locking hubs or replace the ones you have with new auto lockers. The auto locking 4x4 hubs are great when they work but when they don't they are not serviceable. The manual lockers are allot less likely to fail on you in the future.

Lift and support the front of the truck so the front wheels are off the ground.
Key on, engage 4x4 and try to turn the front drive shaft.
If it turns it is a problem with the transfer case.
If it doesn't it is a front axle engagement problem.

could be your front actuator or your actuator motor on the transfer case.

sounds like wheel bearings or 4wd might be stuck engaged... try cycling 4wd or checking grease packing first.