Hi Guys,

I'm hoping for some help with my latest LR3 mystery. I have a drive train vibration when accelerating between 30mph and 60mph that sounds kind of like a wheel that needs balanced but is not a wheel issue. It is definitely a drive train sound, it mostly goes away when I take my foot off the gas and no amount of turning or hard driving affect it. It is a fairly alarming sound and is getting worse. I've been trying to track it down for about 6 weeks now.

A local Indy told me it was the center carrier for the rear drive shaft. We replaced that with a new unit and the sound is still there. (The old center carrier looks fine as well, should have inspected it myself before hand) I also took it to the tire shop and asked them to rotate and balance and inspect all four tires. Which they did and found no issue. It sounds to me like the noise is coming from the front or below the driver seat. Rotating the tires did not move the noise from front to back. Also, the front Diff was replaced last July. It was replaced at this same local Indy shop which I have completely lost confidence in.

Do you guys have any ideas what could be making the sound? I've inspected the front drive shaft and I'm leaning towards it being the source but I cannot see any issue with it. There is a very small amount of play in it when pushing it from the front of the vehicle to the back and no play in it when pushing it up and down. Is it possible that it could have been damaged or installed incorrectly when the front diff was being replaced?

Any ideas are greatly appreciated. Thanks!

 

Wheel bearings maybe? Easy to check, at least....

 

houm_wa, the local shop ruled out wheel bearings, tie rods, and any other suspension parts that could be the culprit. Supposedly everything is in good condition. I had the lower control arms replaced last July as well.

 

...front half-shafts too?

 

Yeah, the rubber boots on the half shafts are fine and there definitely isn't any movement in them from what I can tell. No signs of wear or anything abnormal...

 

Unbolt the front drive shaft from the front diff and rotate it 90 degrees and test... if still there rotate another 90. Look also to see if there is evidence of the shafts balance weight missing.

 

Hey EastCoast, I took the skid plate off this evening and I can see a string of grease above where the shaft bolts to the diff. The front joint for the shaft has definetely lost its grease. You can tell its been slinging out of the joint and accumulating above it. Tried photos but its too dark... All of the weights seem to be in place. Im thinking its time for a new front drive shaft. When I put a new one on do I need to be concerned about how it lines up with the diff? I guess I can rotate 90 degrees if the new one is still causing problems?

Has anyone replaced their front drive shaft? It looks like I need to remove the cross member where the transmission and transfer case mount, and I need to remove the passenger side catalytic converter. Thanks!

 

Don't know if it would matter as much with a new shaft. Always look for markings such as a center punch mark on flange and diff to lione up if possible.

 

Had a bad vibration right around 55-65 mph and it ended up being the tire pressure was too high. craziest thing I ever seen but once I dropped it down to 32 PSI everything went back to normal. I replaced a lot of bearings and did a lot of adjustments that probably weren't needed but at least now I know they are done.

 

What was the tire pressure at before you lowered it to 32 and what size tire?