Buzz9075

Does not appear my 2001 F150 Supercrew 4x4 hi is working. I turn the switch to 4 Hi, lights come on but I don't feel that small jurk and it sure does not act like it is in, while the truck feels a little stiff in the corners (To much snow to play on dry cement lately) to me I don't feel any real traction gain. Test I did today to prove it was not working. Put it in 4*4 hi and drive around the block. Then get my son to watch while I floor it on snow to see if the front wheels spin as well... nope they only roll but the back ones spin and I fish tail up the street.

Tonight I shifted into 4x4 low, I felt the big thunk but I was at the lights and did test driving it. Shift back out to no 4*4 thunk as it came out. thinking back I should have done more tests with it. Will do it tomorrow.

Before I take it in and waste big $, what can I look at my self.

95Mercman

Hey there!

I am by no means an expert on anything but I have a few suggestions that will not cost any money to do.

I would suggest looking at the electrical connections on your transfer case. I found that on my car the salt and corrosion has fouled up connections on my starter and AC pressure switch. It takes little time to disconnect and check to see if the copper has turned green. If so, spray some electrical contact cleaner and try to clean the connections as best as you can. This may solve the problem.

Another suggestion I had, was to check the amount and colour of your transfer case fluid. All it takes usually is an Allen Key to open the top plug "check plug" of the transfer case. The fluid should hopefully be pinky colour, usually ATF however, I have seen some of a green colour in GMs. The level should be about 1/4 to 1/2 inch below the hole, however truly full is when it dribbles out of the plug opening when you remove the plug. If the fluid is worn or low, this may be another reason to your lack of 4X4 HI. Being as the truck is an 01, I doubt this is the case (without knowing the mileage) but its worth a look. It doesn't cost anything, and you should be able to do it in your driveway/garage.

Good luck.

00gtr1

If your 4x4 lights come on and you felt the clunk that means the GEM module commanded on the the motor and the motor works. so I say you have a broken shift fork in the front differential or the vacuum modulator on the front differential. Its common for the shift fork to break on late model f-150's but lately I've seen the vacuum modulators freeze up and not engage the fork. What u can do is remove the black plastic cover that bolted to the front of the differential (it's right below your oil filter) and with the truck running have someone shift the switch and see if the shift fork moves if it does and the 4x4 still doesn't work most likely the shift fork is broke and its time to remove the front diffy. hope this helps.