Today I was at landing pulling the boat out of the water for the year, and as usual I put in 4wd low, so I get a nice slow crawl ratio. Anyway when I first lock it in, I pull it all the way back (I'm in neutral with the brake pressed). It goes in dash board lights up 4wd Low. I go to put it in drive and I hear gears starting to grind, so I put it back in neutral, and the transfer case by itself moves back neutral. So I push the brake, while in neutral and pull it I again, seems fine. As soon as I push the gas when in drive I hear a loud pop and then it pulls out just fine. My dad was standing there and said it looked like the front was locked in but the loud pop came from the rear end some where when it popped in. Anyway tow the boat home 2wd hi every thing was fine. So after I get home I unhook the boat, and decide to go test my 4wd drive on the gravel just to make sure everything is working. I first tried 4wd hi everything was fine, then I tried 4wd low, and when I did it seemed fine, but it was like I had half power or something was slipping, until about 10ft down the road then, it would lock in full and work fine. I have never had this problem before. It seems that only one of drive shaft is locking in at first and then the second one comes in a few feet later. So here is the question how can I test to see which shaft is no coming in if that's what it is? The next question is what do you think broke if anything when I was on the boat ramp? Thanks.

 

On the ramp, I would say what happend is you actually didnt fully engage in 4lo like you thought you did, in my own experience with my lever (which I absolutely love) is sometimes it doesnt always engage, and you need to actually roll ever so slightly while holding the lever back, to achieve full engagement. Not always just somtimes. When you said out later when you tried it, it was like it had 1/2 power, was it because the rear was spinning and not the front? If so were your hubs manually locked in or not? I dont know if you could get vacuum hubs and a floor shifter, so ASSuming you cant get those two you must have had them engaged manually, and Im at a loss for why you seem to have half power, I guess Ill require a better description, motor doesnt rev? rear tires spin? motor revs and wheels seem to move like they are not engaged?

 

My transfer case crapped out completely on me 100 miles from home and I have a 1999.5 as well. There was a design flaw with the mainshaft of the transfer case that caused the main shift fork to run dry and wear away. As in all the teeth are gone and it will drop to neutral without any warning at all.
I would be counting my blessings right now that you made it home. I had to pay $500.00+ to get my truck from the top of Mt. Rainier National Park where it quit.
The parts to fix it cost less than the tow bill !!!
Rather than lay it all out in this thread, I'll post this link to the one that I started when it all went down.
I think on page two, there are pictures of how to fix it. It's a very easy job and doesn't require any special tools other than a spreader and some circlip tools.

https://www.ford-trucks.com/forums/3...ce-needed.html

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Thanks for the reply, I'm going to the mechanic in the morning, he does a lot of work on super duties, he should be able to tell me whats wrong and fix it. My mechanical abilities and tools are not up to this task if that's what it is, but I learn more and more every day. If it is in the tranfer case that's a little above my abilities. At least the mechanics cheap, family discount, he's my mom's counsin, and owns a F-250 HD thats been worked hard 800,000+mi, his next truck is going to be a super duty similiar to mine.

 

Front wheels seem to be engaged, but the rear ones don't engage right away, I would say it seems more like the rear end is unegaged and slipping, like when your transmission slips, not really a lack of power.

 

rebelchevy is right on (not saying that is what the problem was, but good chances) you can just trust the light on the dash saying you are all the way in low, you have to really feel it lock, and the best way is to have slight pressure and let the truck roll ever so slightly

and to give yourself a good idea of where the problem might be, crawl under the truck (truck not running, in 2wd, and in park) grab hold of the front drive shaft and spin it, it should spin freely....next lock the hubs in and try to spin it again (if it still spins freely, you have a hub problem unless you see the shafts from the rear to the hubs arent turning, then there is a problem in the front rear).....after that if everything seems fine unlock the hubs and spin the driveshaft, give a slight twist backwards to unlock them and then spin it forward so it spins free again....then lock the transfer case in and try to spin it, it should go nowhere

all these may not show you the problem, the truck might need to be under more of a load then what you can twist that shaft inorder to slip, but this may give you a good idea of where the problem is...............good luck hopefully its something simple and cheap!