I replaced the switch on the TC like all the other posts say to do and the light still does not come on and the the front end will not engage. The 4x4 Low light comes on but again the 4x4 does not egage. When I start the truck the 4x4 light come on. The driveshaft in the front spins when I put it in 4x4. I'm bout to get a posi-lock and not worry about the vaccum assisted bullsh%t. I would still like my damn dash light to come on. Any suggestions? Even if you post a link would be appreciated. I've searched all the ford message boards and no one responds to this question when I've saw it elsewhere... Thanks

 

Jerry, your not being exactly informative on what your having a problem with
besides the front doesn't engage.
Have you checked over the front actuator for operation and the link that slides the engagement collar to engage the front axle?
.
By the way, you would not be happy with the continued steering difficulty from a front limited slip.
Find out how the system works and trouble shoot from that position rather than run with what some one else has said they did and end up in frustration when it is not the fix and money/time is spent..
.
How it works ' in short':
Dash switch on or manual operate, the GEM operates the transfer case motor to first position.
This operates the firewall solenoid to pass vacuum to the front axle actuator engaging the front axle.
When these actions are complete the dash light comes on. This indicator is not fool proof when the actuator does not function..
See where the failure stops the action.
Have patience and use your common sense to trouble shoot.
Good luck.

 

I think he is referring to a cable locking system not a limited slip diff, which lets you manually engage and disengage the front end, and bypasses the vacuum engagement system see link below

 

The shift fork has broken the original ones were plastic and the replacement is aluminum

 

Yes, I'm referring to the cable locking system. "posi-lock". I ordered the replacement vacuum solenoids that go on the firewall since mine were originals. They did not fix my problem. I don't hear them clicking but I have an exhaust leak so they might be and I don't hear it. I crawled under the truck when it was running and in 4x4 and could slide the accuator by hand a little way but couldn't get 4x4 to engage. Does it extend to engage? I hear you on the broken shift fork. It could be... I don't want to tear the cover off to find out. Is that the only way to tell? I'll do some research on a broken shift fork. Thanks for at least giving me some ideas. I checked all the fuses and relays and all are good.

 

I got it to lock in!!! After reading every post there is on the subjuect on this board I sprayed the front axle vacuum acuator with some weasel **** and moved it through the motions, went out in the field and it crawled up my biggest hills with no problems. Still don't have a light coming on for 4x4 but I'm glad it works. Thanks everyone. I'll call this one solved.