4WD troubleshooting on Laredo'91

You should make a habit of cycling through the 4WD options every few months just to keep things greasy - like the front drive line.

Big cause of no light is a burned out bulb - but here's the easiest way to check what is really happening.

Jack both front wheels off the ground with the rear wheels chocked. MAKE SURE THE TRANSMISSION IS IN NEUTRAL AND RECHECK BEFORE DOING ANYTHING WITH THE SHIFTER!! With the engine running, shift the transfer case to

2HI. Spin one front wheel and the other one should just sit there (I'm pretty sure the 91 still had the axle disconnect). If both wheels spin (usually in opposite direction), then reach under and try to turn the front drive shaft. It should turn by hand. Now start the engine and move the transfer case shift to the 4HI position. Turn the engine off and check the front wheels again. Both should definitely spin if you spin one. If only only one turns, you do have the axle disconnect and it ain't working. You should NOT be able to turn the front drive shaft by hand - if you can turn it, then the transfer case is not going into the 4WD mode. If you can't turn the drive shaft and only one front wheel turns when you spin it, the problem is either the shift motor on the front axle or a vacuum problem. If both front wheels spin but you can't turn the drive shaft by hand, you are pretty certain to have a functioning 4WD and it's either a burned out bulb, a wiring problem to the switch or a bad switch. If the check shows a problem, it's likely either a bad vacuum switch on the transfer case or bad vacuum lines from that switch to the front axle.

I think your linkage could use some lubrication. It is open to the elements down under there.

I am not sure where the 4x4 switch is on the 91, some are down on the axle disconnect if the 91 has that. Passenger side at the back of the tube. There are vacuum lines going there too that lock in the front axle. The light doesn't mean much about 4x4 except that maybe the front axle isn't hooked up. The shifter does the real work of getting into 4x4.

Could you spin the front tire?

Your other 'symptoms' sound normal. This part time 4x4 is only meant to be used on snow covered roads or dirt.

In 4 low it acts like a jackrabbit. If you wind it up in 4 low on too hard a surface, sometimes it won't want to come out and you have to goose it spinning tires in reverse to loosen it up. That would be a 4 low to neutral shift though which should happen at about 2 mph.

4 high can be shifted in and out at an legal speed.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)

Hi all,

I didn't have a chance to check your advice since I am quite poor in terms of tools to do the job but I am pretty sure there would have been useful. I had to go for some oil changes and a couple of things after being stuck again in the snow (you feel quite stupid to see your

4wd car needs some help while a regular car can do the job on a standard parking lot covered by snow). It appeared one of the vacuum lines was dead. The car is still at the shop for an alignment problem I've noticed after my long drive from California to Maine ($$$ in repairs ahead) but I should be good after that unless the Maine safety inspection reveals something nasty.

Lionel

Me again...

So I got my car back with one vaccum line replaced. I don't think I am done yet...

I tried the various mode 4H, 4L and I have noticed the "Part Time" light is not on when I switch from 2W to 4H, turn on from 4H to 4L and then stay on when moving back to 4H. It disappears when switching back to 2W. I suppose the light should turn on when I switch to 2H ? Is it possible the linkage may require some adjustment ? I have the process in my Chilton but obviously I don't want to play with that if I don't have to.

Now, I have also an intermittent noise at speeds under 35mph (like a flow of air through a tube/somehow metalic but no vibration). It apparently tends to appear mostly when I am decelerating. I am unable to diagnose exactly when. It's not at all persistant, it just comes and goes only when I am moving. For sure it's under the car as it's much more distinct when I open the windows, it's coming from the passenger side, in the front. Any ideas ???

Thanks !

Lionel

car needs some help while a regular car can do the job on a