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My 4wd will not shift into 4wd on the fly. When ever you try there is a very loud high pitched grind. As soon as you switch back to 2wd it stops.
Works fine otherwise. I can switch into 4wd when not moving, drive in 4wd, 4L, switch back into 2wd on the fly etc... The only thing I can not do is switch into 4wd on the fly.
I am learning that there is some kind of electro magnetic clutch in the transfer case that might be the problem.
Is there some kind of relay or other part externally that could be the problem to make it not work or is the electromagnetic only internal?
A ford tech on youtube told me I need to concentrate on the esof clutch relay pinpoint test "E" in the shop manual to verify if it is external or internal, but I do not have a factory service manual to look it up.
Any help would be appreciated.
If I can't figure this out, once I get my truck all put back together I will take it back in to the dealer with this new information, but it would be nice to be able to figure this out myself.
I did a google search yesterday and it turned up nothing. Today I search and bingo, the whole thing from the factory service manual shows up.
I can't do the testing since I can't hook into the Ford system, but there does appear to be a clutch relay in the system.
Now the quest is to find that relay. I will swap it out and see if that is it. If not, it is starting to look more and more like the issue is inside the transfer case itself. If the relay doesn't work I will take it into the dealer to have the final diagnostic done to confirm the issue, which of course I will pay for, and then most likely have to go to pull a part or order up a used transfer case.
I have also read that you can get to it from the pop up plate on top of the dash near the windshield.
The transfer case clutch relay is located in a RPO relay block. This block is behind the dash on the passenger side, up high near the base of the windshield.
Relay? It works when the truck is stopped, right? It is just when you try to engage it moving it grinds, correct? If so, then the relay wouldn't be the culprit. If it does those things, then look at the motor. It may be weak and won't allow the gears to mesh at the right speed, to not grind. You might take it off and make sure there is nothing hanging up or causing a bind. If it has power, the relay is putting out. I've seen this a couple times. The system worked great at a stand still, but the second you were moving over 10-15 mph, it would start the grind. The motor is set to spin at a certain speed to mesh the gears properly, and if it is weark, or tired, it will grind the one side, because it is going slower than the opposite gear is going.
I'd check there if the thing I mentioned are correct. Good luck.
Well guys, no joy on the electromagnetic clutch relay.
Relay tested fine, even swapped it out with a known good one anyway and nothing changed. I'll check for a signal at the TC, but I am sure there will be one.
I'll check out the shift fork itself in the differential and the TC motor, but it is starting to look like something is probably wrong inside the TC itself. Since everything seems to be working fine, except for the shift on the fly to engage, I am probably not going to do anything about it for now. I will just shift into 4wd when stopped.
4wd
