[pkronfield]

I searched this issue here and found several old threads that lacked any real conclusion as to the cause for what seems to be a fairly common concern. My Mule clunks loudly in 4wd only, never in 2wd. I posted in the FB Kawasaki group and was told by a poster there that tire psi was a factor and can be helpful in reducing the noise. It was suggested to use 12psi front/ 24psi rear which I did and it seemed to erase the issue entirely for about a week. Then the noise came back with a vengeance! Now it's louder than it had been. I'm told by a former dealer mechanic that the clunking is from the springs that are designed to relieve the tension within the drive train which occurs in 4wd only and derives from the the front drive ratio as different than the rear ratio. I bought this Mule new, now it's nearing 400 hours and has been used only on our farm it's entire life, a combo of crushed rock on steep private roads or dirt roads in our forested areas. Our main road to the pavement is~ 1/2 mile and a 4wd grade. The other rocked road is an even steeper road that climbs up high on our property in the E KY mtns. and cannot be driven except in 4wd. For most of the years we've owned this Mule it never made much of a clunk in either drive mode. This year it began to clunk loudly, I did the tire air adjustment and all seemed OK for a few days. Now, it sounds like a machine gun in 4wd only. Feel free to guess but the Mule runs great as long as not in 4wd mode. It's not wheel bearings, drive belt/CVT or U-joints as I've checked them. In 2wd it's smooth as glass on any road. The air pressure thing having made a difference that magically went away is flat out weird. A former dealer on FB says there was a dealer only bulletin on this but neglects to expand on that fact. I reacted to his saying it was a hard packed road issue in 4wd by saying that my Mule didn't do this for ~ 8-9 years then began to do it-> all on the same piece of land and roads. I also added that I was a retired pro mechanic as a FWIW, but he took that as me suggesting I was a know it all and told me to go fix it if I was such a great mechanic. I'm not on an ego trip, just that I find this noise perplexing and obviously something changed on this Mule over time. The whole idea of these web forums is towards we being helpful to each other and talking about this or that. Do these tension release springs weaken over time and call for replacement? Our Mule is in daily use and I'm building right now so any help that saves me time is great. Ideas are welcome, thanks!

How long since you bought new tires? At 5 years I needed to buy a new set. The old ones were making some noises, and the noise stopped with the new set of tires.

 

[pkronfield]

I seriously doubt it's a tire sound as I know how to analyze sounds having been both an auto and aviation mechanic by training and experience. It's a mechanical "clunk" and often described by others here and on the FB Mule group. It's common sources as I understand it are said to be: tire air pressure proper (front and rear Mule drive rations are different thus affected by improper psi), adjustment of shift levers,(so 4wd is properly engaged) greasing the drive shaft hanger bearing (which is somewhat under the gas tank on my 4010 gas) and maybe something else I don't know about. I'm not a pro Mule mechanic experience wise. I did try the psi at 12 front, 24 rear and mysteriously my "clunk" disappeared for several days, then came back. Our Mule is used on our farm and 4wd is only engaged as required for two steep grades so we know what makes the sound appear-being in 4wd and climbing those two crushed rock hills. Any other areas we have always switched back to 2wd for smoother operation, clunk or no clunk as easier on the machine. The tires are OE and original to the Mule, bought new in 2012. The tread is quite adequate in either 4wd or 2wd. Why do you say you needed tires? What was the symptom, if any other than traction? It is an off road machine thats slow anyway. Typical tire issues such as balance and safety aren't factors, all about traction same as my farm tractor.

We have no garage on our ranch. The tread was quite worn and when we loaded the bed with a rather heavy load, one tire sidewall burst. Next year will build a garage/workshop. There is not one level area on the ranch and it is very rugged with rock, cactus, mesquite etc. really can chew up tires.