4wd indicator lamp

In the last couple of days i have noticed that when i shift into 4wd, the part time light does not show up on my dash, it juss stays off. I know it shifts into 4wd lo, becasue i can feel the torque increase but im having trouble telling if its engaging into 4 hi. when i shift i can hear the colloar sliding over so im pretty sure its engaging but without the light im juss not sure. do u guys think its juss a burnt bulb, or bad wiring. the bulb is easy enough to check. but where would i go and check the wiring on the t-case? thanks for any inpout. Also when your in 4wd low, do u guys here like a humming noise at all. sry for the dumb questions. the workings of the 4wd mechanism arent really my area of expertise

If you have a vacuum disconnect front axle I think the switch that turns on the light is on the axle. There may be another in series with it at the transfer case but I'm not sure.

The noise in 4 low should sound more like a high pithed whine at speed. That would be the reduction gears in the transfer case and it's probably normal.

Like the post above says, check your vacuum actuator. It's on the passenger side on the back of the front axle. If the fork/collar don't slide over in that, your 4wd lights wont come on. Start there.

Feeling the torque of low range does not mean that its in 4wd. Your transfer case can be engaged in 4wd and not your front axle. So If you put it in 4 lo, the rear wheels will still be recieving the gear reduction even though the front axle isn't engaged.

And yes, that humming noise in low range is a normal gear reduction noise.

Search for things like "vacuum actuator" and "front axle disconnect" and you should come up with a lot of info, including how to override the vacuum system if that is your problem.

Well i havent been able to go out and fiddle since its been raining here but. im pretty sure it is engaging becasue i can hear what sounds like the shift fork sliding over. but at the same time im wondering to msyelf. possibly it isnt engaging becasue i was going through a lot of mud and i was having trouble going through. and i have decent all terain tires, and i was slipping a bit, where as a stock unmodified jeep with wearing tires, got through fine. ughh. when i have a free chance im gonna engage it into 4wd and pull the vacume houseing off. Yes i know jack up the one side so the fluid doenst come out. Im kind of hoping its not engaging so i have an excuise to get out and make the posi lock. to override the automatic engagement.

Keep in my that just because you have vacuum pressure to those lines, it doesn't always mean the fork is going to slide over inside.

I would take the actuator off and clean it out anyway. It doesn't seem to take much to gum those up.

If you don't want to go through the trouble of making a "posi-lok" system and routing the cable and mounting and stuff like that, you can throw 8-10 washers in the actuator to shim the fork and collar over. It will be just like the newer d30's without the axle disconnect.

Update

Ok well the the weather fianlly is ok, but work has kept me from pulling the vacume housing off the axle. I did figure though why not throw herinto 4wd and see if it binds whilei go around turns. Sure enough its as iff i were in 2wd. same is 4 lo. And when im in 4 lo. I feel the reduction gears doing there job but theres no power to my front end. Im assumming my vacume actuator is shot at this point. I gues ill try cleaning it out maybe. checking the hoses for vacume. WHats the worst case scenario here. could there be any trasnfercase isssues here, or is it most likely the cacume actuator? any help or opinions is apreciated

Both of my XJ's have vac disco axles and I've not heard them lock yet. One of them has a home made cable to disconnect the axle. If it was me I would replace the vacuum actuator with the cable one.

just a quick question if i were to shim over the fork using washers, wouldnt that pose a problem? correct me if im wrong but wouldnt my wheels alwasy be locked together therour when i go around turns evan in 2hi, wouldnt i be binding? or am i missing something here? im aware that nwer jeeps are a one peace shafts? enlighten me on this. sry to keep this thread going

Yes if shim the color inboard - toward the diferential it will lock the axle shaft, just like the newer Jeeps. in 2wd it will not bind, the diferential will do its job.

I've had to "rig" mine with a nylon tie-wrap, when I found out that my actuator failed, any thing to move the collar over and keep it there and not fall off will work.