Hey guys,

I've had a problem with a vibration in the front end that I have been chasing for a long time and I think I finally found the problem but need some advice.

Pretty sure it is coming from the drivers side and I have replaced shocks, sway bar bushings and links, cv axle (passenger side seems fine) and brand new michelins.

What I noticed is when I jack up the front end and put the transfer case in neutral, then spin the drivers side wheel by hand the suspension moves up and down with each revolution. I put the truck on 4 jack stands today and put it in drive and sure enough, the same thing happened when I gave it some gas.

The type of movement is consistent with what I feel when driving on the highway. ..more of a thump thump thump thank a high frequency vibration.

Question I have is whether or not what I am observing with the front suspension (drivers side only) is a normal phenomenon of the awd setup with this truck or a problem with the front differential or tcase?

Any help or advice greatly appreciated. Truck is perfect otherwise and runs like new. All maintenance is up to date and it is an 05 with only 100k miles. I only put about 5k on it per year so I am planning on keeping it for another 10 years at least and giving it to my kids.

 

Find a good mechanic that has a recording microphone. They strap it to parts like your differential and take it for a drive, then come back and listen to what was recorded.

Chip H.

edit:
Like this one:


It's a kit with four microphones that you zip-tie to the parts in question and transmits to the receiver inside the car, so the mechanic can hear the noises as he drives.

 

Thanks Chip.

I strapped an old cell phone under there and took a video of the CV area while I went for a short drive. Everything looks and sounds normal as far as I can tell. I replaced the wheel bearing last night and that seemed to help with the vibration a bit in the highway but I jacked it up on all fours again and put it in drive and sure enough the same thing.

I'm wondering if the CV axle which I just replaced is binding from the weight of the wheel causing an irregular rotation and cycling of the suspension assembly?

If anyone in the Boston area wants to swing by so we can check out your truck to see if it does the same thing I can be convinced to do some work for a few beers . I have a garage and all tools.

 

Wow. Would NOT have thought of that. Interesting approach.

How many times per revolution? Because the CV joints have 3 lobes on them, and if it's happening 3 times ... there's your answer. Even though the driver's side is a new part, if it's a rebuild (cough-cough-china), it still could be bad right out of the box.

Chip H.

 

I should have mentioned that I was having the vibration problem before changing the CV which is why I changed it (it was leaking grease badly)...but, I never observed the issue with the suspension cycling but only because I didn't put it up on jacks to look before I replaced the CV. So in short, I am not sure if it was there or not before I replaced the CV but since I am sti getting vibration, I am assuming that it was and that I have a possible problem with the diff.

 

It could be something like the axle not seated all the way, or something entirely different.

I think it's time you took it to a driveline expert.

Chip H.

 

Took it up to 95 on the highway tonight and it feels much better. Not perfect though as there is still some vibration and very minor shaking. I think it is tie rod ends and ball joints next. Should have just done everything at once but the new wheel bearing seems to have helped.

Anyone else notice that the wood steering wheel tends to transmit more vibrations? Hold it on the sides and it feels smoother.

In any case, seems like it was not the diff which is a relief but I won't rest until it is perfect. Need to drive a piece of junk car for a while to remind me how nice it actually rides I suppose.