I own a 1998 F150 that I just bought this year and I heard a strange noise when I put it into 4 wheel drive. I have read my manual and it states that I should hear a thump letting me know that the wheels are locked. I didn't hear the thump and proceeded to drive it in 4wd. The noise I got was like it was not locking. It sounded like a rumbling sound and when I turned the wheel it really sounded bad. Does this sound like my 4wd is going out or is out? I have a 2 year warranty on the truck so it's not like I'm going to go broke for having this fixed. Any possible answers would help. Thanks.

 

This morning I was out in the snow trying to listen to the noises I have been hearing. I went back to my manual and more or less from what I have read I can shift to 4wd either parked or on the fly. I really didn't want to do it on the fly but I did anyways and I heard the thump telling me that it was locked in. But it still sounds like something could be loose. If I could spell out the sound I would. Everytime I shift to 4wd in park I get the noise again. Maybe I should just keep shifting on the fly, and just be happy. Is there a problem with this? Please help!!!

 

Well, there could be a few things wrong.

Get the front end on jack stands and check the wheel bearings. Next, give the axle shafts a shake, you may have a bad CV joint.

If you do not find the problem there, then you may need to look into the front diff.

Is there any chance that someone put an easy locker or other traction enhancing part (limited slip)?

 

If it's a grinding noise when you go to put it in 4wd from 2wd i know exactly what it is so respond if thats the problem.