today I was rotating the tires on my '05 FX4 and noticed when I spun the passenger side tire it spun harder then the other side and there was a clunking sound. I have a 2" AS kit on the truck and in order to get the tire off the ground when jacking from the frame rail like the manual suggests, the front CV joints are at a severe angle. So, I spun the tire and watched under the truck and the binding was from the CV joint trying to turn at that angle, but I also noticed that the whole front axle would move back/forth and up/down a little as the cv joint would bind while turning. Next I put another jack under the lower A arm and pushed up on it some to put the cv joint at a less extreme angle and the binding and movement of the axle went away. I checked the drivers side and it doesn't do it, but that is the short side of the axle and would take alot more leverage to move it. My question is, is the front axle mounted so it is allowed to move a little under pressure or is it supposed to be rock solid? I checked the mount above the passenger side tube and it didn't appear to be loose/broken and I couldn't move the axle by hand. I've drove the truck quite a bit in 4x4 and have never noticed anything out of the ordinary and the angle the cv joint is at when it binds will only happen if the tire comes off the ground.

 

Ah, these are the kind of problems that can occur with aftermarket suspension mods...

Driveline angle is important...on anything. When you alter the driveline angle, you change the way the joints(CV or universal) move. This can put them out of spec, twisting them in a manner they aren't designed to...which can shorten component life and cause lots of headaches.

You figure without the lift the angle of your CV joints with the wheel off the ground must be close to the angle it's sitting at with the lift and the wheels on the ground...so even when all 4 are on the ground you are likely at or near the limits of the design, which would severely shorten the life of the joints.

Not an issue in 2wd because they don't spin, but if you are frequently using 4x4, new CV joints are likely in your future...


Used to know a guy who lifted his Toyota pickup some years ago. Apparently they don't use a similar system to Ford, where it locks out the hubs, and the drive axles were always spinning. He apparently was replacing CV joints frequently because of that lift...he promised to never, ever lift another truck with IFS because of it...