My '98 E4OD w/ electric shift was stuck in 4x4 low while pulling a loaded fertilizer buggy. I thought it shifted out because the dash lights - 4x4 and low range- went off. When I got on the highway though, I couldn't run but 35 mph. I pulled off the shift actuator and manually turned the transfer case back to 2wd high. Nothing happened when I turned the 4x4 switch either before or after pulling the shifter (no noises or lights). I wired the shifter up because one wire didn't come loose. I believe it goes into the transfer case. I need to know how to check to see if my problem is with the switch or the shift actuator. I checked all the fuses and relays (that I know of) and all checked out good. I believe the hubs are vacuum activated and possibly I need to check at my front differential for a problem also. Anyway, now my truck drives fine on the highway. But I'm not sure what to replace/clean/or check. Thanks for any assistance.

 

The diff is the part that is vacuum actuated. The hubs are permanently installed to the drive shafts similar to the design of a frontwheel drive vehicle.

I am unsure of the location of the vacuum solenoids that actuate it on a '98, but the '99s and up are mounted to the firewall on the passenger side. The vacuum hoses run from these valves down to the diff. It uses a ram and actuating lever that pushes or pulls a gear (the ring gear iirc) to engage the front diff. Lately, I have heard more problems with a stuck or slow ram/ actuating arm.

That's only part of your problem, though. The fact that the xfer case didn't come out of the low gear set is a new one. I'm going ot roll the dice with this, and say that if you solve the reason that the diff stayed engage the xfer case will fix itself. I know they are two different components, but the operation of one affects the other.

We had a discussion on the operation of the system a few years ago... if you skip towards the end of the thread you'll be able to read about how the system is supposed to work - http://www.fordtrucks.com/forums/sho...d.php?t=309867

-Kerry

 

Thanks. I have a cd-rom service manual for an '01. I'll look at it later and call a friend who used to work for the Ford dealership as a certified mechanic. Since my lights went off and won't come back on, I'll start with the vacuum thing and the switch. Possibly the shifter isn't getting an input to shift to 2wd. I should be able to pull a relay and jump some terminals to get it to shift. But since my lights don't come pon anymore, I'm sure there is a problem either with the vacuum solenopid being stuck or losing vacuum or the shifter motor has quit on my transfer case. I appreciate your help. Thanks.

 

(posted twice so I deleted one, Sorry)

 

Well I took my truck to a certified mechanic. Nothing showed up on a scan. Sometimes it said no power to 4x4 switch other times no ground. He said possibly could be PCM, or maybe a loose ground. I've since found that sometimes I can get the truck to switch out of 4x4 by turning my key off/on. Not always though. But so far, every time if I remove the positive battery cable and put it back my truck will disengage from 4x4. I'm wondering where the 4x4 relay is located. I can find the fuses but no relay. Is it part of the shift motor or possibly under the dash away from the fuse box? And I'm not sure where to look for loose ground wires. If I clean my battery posts really good I have no problem for a few weeks. Thanks for any assistance.

 

The relay is located under the the dished part of the dash - passenger side. Pop the cover and you may see two relays. I can't recall which relay is which, but look at the wiring colors on the output side and match that to the wiring to the solenoids under the hood.

If you have gotten water in any area, that could be a reason you're chasing this issue.

-Kerry