I've interrogated a lot of parts on my JK, but I dont think it's the upper u-joint or anything south of the steering box.

The steering box is something I haven't looked into, but my steering is pretty tight.

I have a theory that the upper coupler is expanding when the engine bay gets hot, and it's not making solid contact with the upper steering shaft. I HAVE got a clunk from that area when I mess around with things when they're hot. I wanted to check to see how wide the gap is at that pinch bolt when things are all tightened down.

Something I have found -- the firewall DEFINITELY amplifies the sound of anything connected to it. I have a PCV catch can mounted to the firewall and can hear the air pass through it clear as day inside the cabin. From under the hood, with my ear up to it, it's barely audible.

 

What grease did you use?

5th wheeler grease fixed my clunk luckily. Had the dealer check it out during routine maintenance and like fivenote they said there wasn't a problem, just makes you want to pull out your hair.

 

I believe it was NAPA brand "open gear lube". I know I bought it at a NAPA, and it was a mainly blue can. I thought others on here were using it successfully.. for some reason, it didn't go over well for me.

 

Been living with this clunk for about two years now. Been doing a decent job at ignoring it, but had some spare time to dig into it again.

I narrowed my clunk down to the upper coupling of the intermediate shaft. Where it connects to the upper shaft by the firewall. I could duplicate it by just shaking the steering wheel back and forth quickly. (slowly, nothing). The collar rocks side to side SLIGHTLY when the shaft is turned. (side to side, that is, horizontal to the clamping of the collar). I actually couldn't see it - only feel it. I could only see it once the pinch bolt was loosened, and it's the same exact noise.

I think the best fix in my case is to shim the coupling so that it makes tighter contact with the upper steering shaft. Perhaps I'll dab some epoxy in there and file it down to size.

Short term fix, I cleaned / degreased the coupling and the upper shaft's mating surfaces. Also reassembled the collar with it lower on the upper shaft; not pushed up high. There is a bit of a ridge machined into the upper shaft - I kept the collar away from that slightly to see if that would help any. So far so good - but we know how these knocks go...

A side note to mention:

I spent plenty of time under the dash interrogating parts. There is a "cush drive" in the upper steering shaft that is supposed to help reduce vibes to the steering wheel. There is yet another metal collar, but with a pin through it. Rubber is the primary connection between the shafts and the pin is allowed to float but make contact when necessary. The pin had a small strip of rubber around it that served to dampen contact with the collar. The rubber strip was falling out and I was convinced that was the source of the clunk.

I had a small section of rubber hose that fit around the outer diameter of the pin perfectly. Slipped it over, but did not reduce the knock at all.

However - my steering is a bit more precise and a bit sharper today. The steering wheel feels more connected to what's going on on the road. It's a mild but nice improvement.

Here's a pic of that "cush drive". You can see the rubber damper for the pin hanging:
(Steering wheel turned 90-degrees to the right)




The hose I trimmed and slipped over the pin:

 

Been researching this myself on multiple forums and found this by Misch 4X4 Steering Chatter Eliminator
Any body tried it yet. Spoke with Doug Misch the owner of the company and he says that once the heat expands the metal on the steering shaft this happens to alot of the JKs including his... thus the reason for his product. Love to hear form anybody who has tried this.

 

That actually looks really interesting -- and potentially promising. I inject the fifth-wheel grease a couple times a year on my Jeep's intermediate steering shaft and although it does help a bit, I wouldn't say it eliminates it, particularly on hot days. (During the winter it's rarely an issue.)

I am contemplating trying out this product, I wonder if there is any sort of money-back policy should it not do anything to effectively help.

 

I just have the dealer replace the steering shaft whenever it starts to make noise. My JK is 4.5 years old and had 92k miles and I'm on my 3rd one. I have a bumper to bumper lifetime warranty ;-)

AdamIsAdam

 

Lmao @ $60.. eff that! Hardware store here I come with a worn out, sweaty $5 bill!

 

This x2...

 

If it has not been said search clunky steering... I had it and showed my dealer the thread on this forum.... They did it under warranty no issues and its been well over 40k KMs no issues at all