My truck started clunking on the weekend. Everytime I pulled away from a stop there would be a sort of a clunk sound. I also noticed a clicking sound whenever I was braking. I initially thought the clunk might be a chunk of ice somewhere underneath that was moving about when the truck shifted ahead or back. It sounded like it was getting worse so I called a shop that I sometimes deal with and asked if they had a minute to put it on the hoist and have a look underneath. They did and I took it over there. They suspected universal joints and the mechanic pried them about without finding anything loose. Then one fellow got in and drove the truck ahead and back an inch or two while the mechanic watched the driveshaft. It was apparent that there was movement on the pinion before the wheels moved. We assumed a differential problem so they pulled the cover and drained the oil expecting pieces to fall out. No broken chunks fell out or remained in the differential housing. They turned the ring gear and saw no chipped or worn teeth anywhere. The mechanic commented that he was going to pull an axle and check the splines on the axle. Then he found the problem. When he pulled the centre cap to get to the lug nuts he found that they were all only finger tight and that the wheel was moving back and forth. The studs had worn slots in the aluminum wheel that were at least double the original size of the bolt hole. I have driven the truck about 3000 miles since the wheels were last off of it. This wheel must have been loose for the whole while but never to the point where it was obvious. We have put the spare on and will send the wheel out to see if it can be repaired. If not I will need a new wheel.

So, check your lug nuts and make sure everything is tight. The rest of my wheels were fine so I assume this one just did not get properly tightened when it was last looked at.