Just this last week we had a snow storm and it gave me a chance to actually try out the 4 wheel drive on my truck. It is a 1999 F150 XLT scab 4x4 that I had bought used with 102,000 miles and now has almost 105,000 miles now. I put it in 4 wheel high “ Manual Lever on the floor” and shifted into reverse to pull out of the drive and I hear a squeaking sound! When I put it into drive it stops. This last fall I already replaced the U-Joints on the Drive Shaft. Any clues of what might be going on to make a Squeak sound in reverse “4x4” ? Are there other U-Joint for 4x4 that might need to be replace? Any help / input would be greatly appreciated!