jgriff

I have been having some problems with my 98 f150 with electronic switch when going into 4 wheel drive it works but wont go out of until I stop and go in reverse.
Yesterday I needed 4x4 in the snow and when I put in 4 high there was a thumping noise comming from the front end so I took it out and I still had the noise, lucky I was just down the street so I parked it. Any Ideas what it might be. Thanks

udderbrudder

Step 1 is to determine if frequency of thumping is at wheel speed or driveshaft speed.

jgriff

Drive shaft speed and it only does it when in 4x4 drive now. Thanks for responding

akdoggie

Let me ask a stupid question. All 4 of your tires on the ground, are they exactly the same? Same size, brand, etc? In a 4x4, any variation of tire sizes while engaged in 4 wheel drive, can cause all kinds of noises, also make popping banging lurching noises and movements. As well as major damage to components. It may just be a stupid question, but who knows. Only the OP knows for sure.

Bad CV's cause all kinds of clicking and sometimes some banging (when they are falling out to the ground). So can the front actuator if the fork is broken inside the diff case. May possibilities. Just some of the common and then the not so common. Good luck

jgriff

Finally got it fixed it was the vacume lines that kick it in and out of 4x4 that were giving me the trouble.

jgriff

Finally got it fixed it was the vacume lines that kick it in and out of 4x4 that were giving me the trouble.