All,

Have a strange issue that's been around for several weeks which I was finally able to pinpoint. At low speed (less than 10 mph) I get a single clunk/pop from the front end. It only occurs during turning and usually only in tight turns. However, yesterday I was able to isolate it sitting at park. Had the wheels pointed straight forward and sawed the steering wheel right and left, from the CW to the 4 o'clock then CCW to the 8 o'clock then back and forth. Never completing a revolution, so basically minor steering inputs while the truck is sitting still. At each change of direction there would be a pop or clunk (at most two), sometimes in the middle of the change as the wheel changed direction. I immediately suspected a tie rod or drag link end, but all have been replaced or are in good shape. Had the wife do the steering while I crawled under the truck and I was able to isolate the noise/vibration to the steering box. I saw no discernible movement of the assembly, but when I placed my hand on the box and she cranked the wheel I could feel the pops by hand. Unit does not leak and is full of fluid. All ball joints and steering inputs appear tight and in good shape, no rust in the area.

Long description, but short questions. One, have any of you had this problem before? Two, I know the unit can be adjusted for backlash, is it possible I just have some play in the innards of the box? Three, could air pockets cause this noise? It surely sounds mechanical like mechanical slippage, but there is no feedback through the steering wheel or "skipping" on either the input or output side of the box.

Thoughts and opinions would be nice...

 

Check your pan hard rod bushings.

 

There isn't a panhard bar on the front end of a D1. Are you talking about the track rod or drag link ends? Mine are new or in good shape.

 

Maybe that's your problem.
Because unless someone removed it, ALL DI's left the LR Factory with a Panhard Rod.

 

Bad panhard rod bushes will make a pop/knock sound when rocking the wheel back and forth. The frame side bushing is usually easy to replace because it's been lubed with power steering fluid for years. The axle side bushing might give you nightmares, though, especially getting the bolt out.

 

$19.95 not bad.

 

Uhhhhhhhhh.... I need to crawl under there and check ASAP. Maybe I need my vision checked and owe you an apology! I'm on business travel but will confirm Thursday.

 

If the panhard rod is missing, you have much bigger problems than a clunk/pop... and it would be nearly impossible to drive. It's there.

FWIW, before getting to any responses, the panhard rod was the first thing that came to mind. The frame side attaches right next to the box, so you'd feel it clunking while touching the box.

 

here is what it looks like. this truck happens to be a RRC, but your D1 is essentially the same. Bushings in question are highlighted by the red ovals.

 

Another part(s) to inspect are the Lower Steering Shaft U Joints (especially the lower).
The joints are not greasable and if worn they can make a pop/click sound when turning. I had that happen on a '97 and it drove me mental.
If you have the original steering shaft the U joint is replaced with STC2800.