I've been chasing down both a speed-dependent humming and a clunk in the front left. I have found that yanking on the front left axle can produce something like the clunk, because there is noticeable longitudinal "play" in this axle. In other words, when I yank the axle towards the wheel, it shifts a bit outward; when I shove it back in (towards the engine), it goes back to where it was with a clunk.

How much (if any) play is normal in a front axle on an X?

 

OK. Was under there again for a while today. Not only does the axle move in and out - which doesn't seem surprising, so that's probably not the problem - but it also moves up and down with a clunk at the inboard CV joint. It also doesn't really feeling like a tripod joint moving in grease; it almost feels like a tripod with no grease and a bunch of play.

So, what's the normal amount of off-axial play in an inboard front CV joint?

 

Is the clunk when you turn a certain direction? Sounds like a bad CV joint to me.

 

No. The clunk is over bumps. The humming is slightly turn-dependent, but most speed-dependent.

The question I have is how much off-axial play is normal for an inboard CV joint.

 

I have the same problem. My axle moves in and out slightly and up and down when i yank on it. I also have a oil leak where the axle goes into the tranny. I have replaced the seal 3 times and it stills leaks. I have no idea how to fix the problem.

 

Well, after more testing it is clear that the clunk is very much reduced by braking. At first I thought that this didn't rule out the inboard CV joint since I was often on the gas at the same time, which puts a lot of torque through the axles, but braking and coasting also reduces the noise. This pretty clearly points at the caliper, wheel bearing, and/or strut, since these are what are affected the most by braking. My money is on the upper end of the strut, but haven't had a chance to tear it apart yet.

 

Maybe it's your top hat or like you said your brakes caliper.

 

It sounds exactly like a loose caliper, but isn't. Caliper is rock-solid and the worn section of the rotor also tells me that the caliper isn't moving; nor is the wheel bearing. I checked to see if the sandwiched bushing at the top of the strut was at fault, allowing the hat to hit the plate or chassis, but it's fine and there are no shiny places on the hat or anywhere else up inside the shock tower. My strut does not seem to be blown.

I checked the swaybar again, even though that would make no sense, given that the clunks are greatly reduced by being on the brakes. This is the hardest diagnosis I've ever faced. I'm back to suspecting the inboard CV joint.

 

Maybe check your crossmember cuz I had a clunk when I went over bumps or up steep drive ways sometimes and I went threw everything trying to see if anything was loose and it was the bolts on my crossmember. So try checking that out?

 

Excellent suggestion. I just haven't had access to a lift lately.

 

How many miles on your struts?? Are you lowered?

 

20k on the OE suspension