rebuilt shift motor, replaced hubs, still no 4x4

[decotrain]

ok guys, 91 explorer with 4.0, 4sp auto, no 4x4. it started like this: i got the truck and you pust 4 hi button and nothing. checked computer in back, corrosion on plugs, cleaned them up then i could hear the relays but nothing else. from the info in your forum (very helpful, thank you very much)i pulled the shift motor and replaced the stop screw. then i pushed the 4 hi button and the light on the dash and the button lights up, i hear the relays and the shift motor, and i can feel the transfer case has engaged, but still no 4x4. with front wheels off the ground in 2 hi the front axle shaft will spin but hubs wont lock. in 4 hi the axle shaft will not spin so i cleaned the hubs, nothing. I went to junkyard and got 3 sets of hubs (6 total) and still no 4x4. is there vacuum or anything else i can check? i cant find much more info, it usually about the shift motor and hubs and from what i can tell mine are both fine.

 

[Robrt32]

Front drive shaft turning ?

 

[decotrain]

until you asked i never thought to check it. i just ran outside tied like a 3 ft. piece of thick string around the front drive shaft, put it in 4wd and took a little drive. its wrapped around the shaft like 30 times, so yes the front driveshaft spins.

 

[decotrain]

oops

 

[little x]

The front drive shaft spins in 2wd (like you said earlier), or 4x4? With the hubs locked or unlocked? Do both the front drive shaft and front axle shafts spin?

 

[decotrain]

i can turn the front driveshaft and the front axleshafts by hand in 2wd. i cannot turn either of them by hand when its in 4x4. i think for some reason the engagement cam will not idle up into the auto locking hubs. in 4x4 the front driveshaft does spin, give me 5 min. and ill tell you if the front axleshafts also spin in 4x4.

 

[decotrain]

ok, when its in 4wd the front driveshaft and the front axle shafts do spin which would make me believe its the auto hubs, but what are the chances that 0 hubs work correctly out of the 8 hubs i now have? is there anything else it could be?

 

[tbe2002]

When you are replacing the Hubs are you replacing the cams that are behind the hub too? The cam could be broke, they are plastic so it wouldn't suprise me.

 

[decotrain]

i am not exactly sure what the cam is. is that the plastic ring that stays on the axleshaft when you pull the hub off, it got the little spring around it that holds it tightly on the axleshaft? if thats the cam then no, all i have tried replacing is the part of the hub that slides off and says 4x4 on the outside.

 

[tbe2002]

Yeah that is the cam. I am going to guess that is the problem then. There are little ears on the end of the points on the cam that tend to break off. Those cams are hard to come by. Might be better to just upgrade to manual locking hubs. That is what most people tend to do. I accually have my new manual hubs sitting at home just waiting to be installed. It has just been to cold here to do it.

 

[decotrain]

the cold thing i can relate to, i am guessing that has got to be the problem. its the only thing i can think of that i have completely overlooked. i am going to take a good look at it and if i have any more problems ill write. just want to say thanks to everyone on this site for their time and info, i couldnt do it without ya and i hope everyone has a merry christmas.