4 wheel drive will not engage F150

SOURCE: '95 Suzuki Sidekick 4wheel drive problem

I maybe able to help. Did it make any noise when you tried (grinding or groan hum exe..) or just not work. If so the first thing I would do is to change the transfer case oil, check for metal in the oil, if there is that's really not good, take to shop. If no shinny metal replace with good quality oil, if it's red use atf if black or brown use 75W 90 and some. Auto trans fluid is recommended in cold climates or adding torque modifier check with parts store or dealer prefferably for what to use unless comfortable with choice then change front differentail fluid, with recommended fluid and torque modifier for limited slip differentails 2oz or alittle more. both holes fill till you can stick your finger in an just bairly bend it 1/8 or so inches and touch fluid. don't try to fill all the way if it comes out of the whole your filling clean up mess and allow as much to drain out as possible. If that happens you may have it vent through the vent and may see/ smell what every you put in it. If your comfortable with taking the diff cover off and replacing the gasket if needed (usually is) make sure its clean, don't use water or anything water based brake clean is good but check for metal and brownish or simial colored stuff in bottom of housing and of course metal. The teeth on the ring gear and pinion( ring gear is the small one in the back, ring gear is big and will be closest to you. if you have hunks of metal in there its smoked and replacement of ring gear and pinion is required (not cheap) there is alot more to look for but that should start you off in the right direction.

SOURCE: transmission

check that you have the freewheelng hubs engaged, this has to be manually on each front wheel hub
Regards Bill au.

SOURCE: my 4 wheel drive does not engage on the wheels

Keep trying , shift vehicle in the neutral position and back again. Try driving your vehicle in high range for awhile as well. Main problem is people don't engage there 4x4 enough and parts get sticky.

SOURCE: front end does not engage in 4-wheel drive

The front diff in this model requires air pressure to engage. There is an electric pump for this purpose and once the pressure rises and remains where it's meant to, the pump shuts off and the dash light indicating 4WD will remain lit. It is sealed. There should be no leaks. If there is air coming out the top, do you mean out of the diff breather pipe? (The diff breather should be connected to a hose that goes up and is clipped next to the radiator.) If it is coming out of the diff breather, you have a punctured (worn out) diff engaging diaphragm which can only be replaced by stripping the diff casing.

SOURCE: Suzuki Gr.Vitara.Front wheels dont engage when reversing in 4WD

The short answer is "no", but working out why could be a little bit difficult. Any further diagnosis should be performed on a hoist or with all 4 wheels off the ground and the transfer box in 4H. Be aware that any of the following checks where front and rear wheels may turn at different speeds will generate an ABS error code and a light on the dash that may need a Dealer to turn off - if you have ABS. You'll also need a couple of hydraulic brake line locking clamps. The first check would be to make sure the front prop shaft turns in reverse as it does in forwards 4WD. Why it wouldn't, I couldn't tell you!
Stop the engine, and while someone is holding their foot on the brake, clamp off both front hydraulic lines to each of the front calipers. Release the hand brake (park brake) and release the foot from the brake pedal (keep foot off brakes from now on) and restart the engine (in nuetral or N), and whilst the engine is idling, select 1st and slowly let the clutch out (if it's a manual), or select D (if it's an auto). If the line locks are holding the pressure in the front brakes, then the manual should stall, and the auto's back wheels shouldn't be turning (but the engine would feel like it's in gear). That would confirm that the front wheels are driving when in forwards 4WD.
Then we do the same test but going backwards, so select reverse and let the clutch out (or R if auto), and if what you say is true, then the back wheels should be spinning away at idle. If the engine stalled, or the back wheels aren't turning, then everything is OK.
Remember to remove the line locking clamps after this test.
I would think that you may have only seen the wheel that wasn't turning when going backwards. These cars have open diffs - so the wheel with the most resistance to rotating won't turn, but the one on the other side will. This is the same for both the front axle and rear axle for most Grand Vitaras. Very few have a factory rear LSD, and I don't think any got a front LSD.
I've just had inspiration - if the front wheels don't drive ONLY in reverse 4WD, the only thing wrong would have to be the front diff engaging mechanism or its related wiring/switching controls. If the relays that control the pump that supplies air pressure to the diff engaging diaphragm in the front diff housing don't get the "I'm in 4WD" signal from the transfer box, the pressure is relieved to the diff and you're back into 2WD. My next check would be to see if your reverse lights are working when in reverse. See if your reverse lights come on when in 4WD or 2WD. If they aren't working, or coming on at the wrong time, then SOMEHOW, the wiring/plugs on the gearbox/transfer case may have been mixed up (during a clutch replacement?) or the wiring somewhere else is wrong. I would probably do the checking of reverse lights before the first test above. Good luck. Let me know how you go.