Bronco knocking when engaged in 4X4

Reply Subscribe

Thread Tools

Search this Thread

Aug 21, 2011 | 10:20 PM

bamafarmboy

Thread Starter

New User

Joined: Aug 2011

Posts: 21

Likes: 0

Bronco knocking when engaged in 4X4

I have a 1989 full size bronco with a 351 and C6 trans. When I got it the rear end was out and you could only move it with the front wheels engaged. It made a little noise but I saw that it needed a U-joint so I didn't worry. I swapped out the rear end( and yes it was the right ratio) and fixed the U-joints and now it makes a knocking sound when it's under pressure in 4 wheel drive. It sounds like its coming from the driver side. I swapped out the manual hub with one that I knew was good and no change. I took the driver side axle out and checked the spines, the u-joint, and the wheel bearings. All where good. It only does this when the transfer case is engaged and the hubs are locked. I can unlock either one of the hubs and the sound stops. I need some thoughts. Any help would be appreciated.

Aug 22, 2011 | 06:50 AM

Lazy K

Post Fiend

Joined: Jan 2005

Posts: 8,402

Likes: 10

Hard to say. Are all three axle shaft universal joints good? Are the axle pivot (hinge) bushings good? Is the front driveshaft slip joint lubed and free to move?