Hey all
First time on the site, awsome Forum... Perhaps someone can help me with my situation, I have a 97 F150XL 4x4 v6 w/ manual 4x4 shifter on the floor, When I pull the lever into four wheel drive the light on the dash appears and It feels like I've engaged the transfer case, but the truck doesn't go into 4 wheel drive (I've driven on slippery snowy road conditions and I only have power to the rear wheels.) My question is where should I look to begin diagnose the problem,
Does the on the floor manual system use any type of electric or vacuum solenoid to lock in the front differential. I've tried to catch some sort of answer from some of the other postings about others 4x4 issues but I still don't have a clear understanding of what components make up the Ford's manual 4x4 system
Any help would be appreciated

 

Start with looking at the vacuum lines between the solenoids on the firewall, near the passenger side hood hinge, for breaks and cracks. The 2 solenoids control engaging and disengaging the front diff. The vacuum lines go to a vacuum motor that manipulates a fork which does the actual locking and unlocking. If the vacuum motor is stuck or broke, or the fork is stuck or broke the front diff will not engage. Assuming everything is okay, put a vacuum gauge on the solenoids.. When you shift to 4x4, one of them will have vacuum, when you disengage the other will have vacuum. That system is the usual culprit for the front diff not locking in. To be sure that the transfer case is shifting, the best way is to put it up on stands, and shift it to 4x4 and make sure the front driveshaft engages.
The solenoids and vacuum lines with vacuum motor and fork are the same whether the truck has a MSOF or ESOF.

 

Actually the shift motor is different from the msof to the esof. I'm dealing with it right now, again. I've replaced my vacuum shift motor once already (about 3 years ago) and now I need to again as it doesn't have the "strength" to pull/push the fork. I can do it by hand and the motor keeps it engaged or disengaged, but will not move it. It doesn't help that I don't drive the truck much and engage it often. That's a good reason for periodically engaging the 4wd so the motor doesn't corrode/fail like mine. When I used it frequently, I had no issues.

 

Thanks for the heads up, I assume that the motor is mounted on the front diff and is a bolt on item and I can unbolt and replace if needed without taking to a shop then, a couple of questions if you don't mind... First assuming that you're correct and it is the motor not the solenoids, I could in theory climb umder and engage the motor manually untill I can get it replaced and secondly I havn't seen this motor listed anywhere as an aftermarket item so I'm looking at a oem replacement and dare I ask how much Ford charges for it... Thanks for taking the time to reply

 

The front diff setup is the same between MSOF and ESOF, the difference between the 2 is the transfer case mode of shifting, which has nothing to do with the front diff. MSOF does the TC shift manually, and the ESOF uses and electric motor.

 

I can't comment on the transfer cases, but I know the "shift/engagement motor" is different between MSOF and ESOF. The MSOF is the vacuum motor. Different part numbers.

Check out fordpartsonline. They list them for like $118 or something and msrp is $161. I had issues getting the "motor" piston to stay engaged with the transfer case arm.

 

i put mine in 4hi about once a month. is it ok not to use 4 low a lot or should i put it in 4 low about once a month

 

Don't know why it would be different, the front diff is engaged thru solenoids, vacuum lines, and motor, whether MSOF or ESOF.
I just drilled down to the and there is no difference on the vacuum (shift) motor. The big difference is between the two types of transfer case. Manual or electric, which has nothing to do with the front diff set up. In fact the shift motor ia the same from 97-04 heritage.

 

Then every place I've ever tried to buy that part from has lied to me. I get the "we have the motor for the pushbutton, but not for the lever. I can order it but you have to pay in advance and it could X days before it gets here...." They explained to me that ESOF was an electric motor that moved the lever, not a vacuum motor.

 

I do. It wont hurt as long as you're not on dry pavement etc. I just stay on our gravel driveway and turn around in our back yard a few times a month.

 

Again, there is an electric motor in the transfer case that shifts the transfer case with ESOF. It still has the 2 solenoids, vacuum lines, shift fork, vacuum motor to engage the front diff. Two separate subsystems. That is why you will see posts about both MSOF and ESOF front diff not engaging.
The MSOF has the lever to shift the transfer case, and an indicator to say it has shifted so the solenoids, etc can shift the front diff.

Diff shift motor

Transfer case

 

ok, whatever. Why does the one in my ford service manual then not look anything like mine in the section under ESOF?

 

Can't answer that. I had a 98 MSOF, which had the solenoids, vacuum lines and diff shift motor, and an 01 ESOF which had the solenoids, vacuum lines, and diff shift motor, and a Transfer case shift motor, which happened to go out. As did one of the vacuum lines on the 98.
All I can say is that the Ford parts online had no separate setup for ESOF or MSOF as far as the front diff goes. If you have a scanner, post a diagram that we can see what you are talking about.

 

I'll see if I can remove mine this week. It's not working anyhow so it might just be that it needs to be persuaded or it could be shot like my other one. I know there are (or were) two different motors. I picked up the wrong one once. Well, I didn't even leave the dealership. Maybe they gave me the wrong model or something.