Trying to diagnose issue wirh SWMBO's SUV

So, SWMBO's 2008 V6 Mariner is having some somewhat minor issues that I want to resolve before whatever they are becomes a larger issue- and obviously would prefer to do so without dropping it off at the Ford dealership and shelling out hundreds for them to just try and figure it out (and likely replace a bunch of things that ultimately do nothing). It is a FWD-only model, and has about 108,000 miles on it.

She brought to my attention that she'd noticed it vibrating/shaking when she would brake at somewhere around 40mph and was concerned that the brakes needed to be replaced. When I checked the car over before our trip this weekend, I pulled the driver's wheel (where it seemed to be coming from) and looked over the rotor and pad (didn't pull the pads off, just checked thicknesses) and didn't notice anything wrong- I had figured that maybe the rotor was warped or the likes, but was not seening anything along those lines and the pads have plenty of life on them.

I had noticed myself for a while that it seemed to be vibrating a bit more than usual under power at some points, but really noticed it on the drive. It clearly vibrates a LOT when braking from about 50mph down to a bit under 40mph and then essentially goes away. But it ALSO vibrates a good bit when the engine is under a good bit of load, especially when already going at a good clip (i.e., starting up a hill when going 70+ and trying to maintain speed).

Though I'm not certain it's related, there's also a suspension clunk in the front end that I need to figure out too- I had thought/hoped that it was just the sway bar end link nuts loosening up again (because that's an easy & cheap fix vs. most other suspension parts). Not certain if it's related or not, but not ruling it out.

So, my thoughts on what it could be:

1. Wheel bearing and/or CV joint- could account for both vibration and clunking, but I'm not seeing any evidence of the joint boots leaking or being damaged, and I'm not hearing any grinding from the bearings that's my usual telltale that they have issues.

2. Wheel/tire balance- Would think that it would vibrate more consistently, but suppose that it could be a resonance thing. If I do anything with the suspension I'm going to have to get it aligned and would have the shop check all the wheels, but the tires were replaced roughly a year ago... and several have been replaced under the road hazard warrenty since then as well.

3. Something internal in the transmission- could account for the vibrations, but again would expect more consistent issues. What I clearly LEAST want this problem to be.

4. Engine/Transmission mount(s)- could account for both vibration and clunking

5. Strut/strut mounts- most obvious potential source for the clunking- I thought I had replaced all of the struts & shocks a few years back, but can't find any documentation to support this...

It is of course quite possible that there are several unrelated things causing what we're seeing...

Thoughts or suggestions?

Start with checking motor mounts  and strut mounts.  Had a vibration in my Focus that I was sure was tire imbalance/alignment.  Turned out to be passenger side motor mount.

Same suggestion, but mine turned out to be a bad ball joint

Control arm bushings?

Control arm bushing and or tie rod end are what that sounds like to me.  

A warped brake rotor shouldn't be ruled out either.

Yes, tie rod ends are something I had considered as well but left off the list. I just need to try and figure out exactly what it is so I don't just drop $500 and replace the entire front suspension and possibly still have it not resolve it.

The tie rod ends though I'm pretty sure I actually have on hand... I think I picked them up when I did work on it a few years ago but didn't end up putting them on.

Part of the difficulty is that SWMBO uses the Mariner pretty much every day of the week for work (she hauls around the chairs she uses for her dance outreach in it), and most of what I've come up with that it could use being done to it (including a full tuneup- which thanks to Ford's brilliant engineers requires taking apart the top half of the engine to simply replace spark plugs...) will require multiple days of it being out of commission.

Failing control arm bushings are known for causing vibration under load and braking, as well as clunking noises. I'd start there. 

I had similar symptoms and believe it or not it ended up being broken belt within the tire. And the vibration was intermittent too.

ebonyandivory said:

I had similar symptoms and believe it or not it ended up being broken belt within the tire. And the vibration was intermittent too.

That would be just our luck... we've had 3 tires replaced under the road hazard warranty due to them being damaged in less than a year...

Have you tried shaking the wheel while it's jacked up off the ground? Pull on the sides, top, bottom, etc. and if it's loose in any direction that can help point out where the problem is. If it clunks or squeaks when doing it that can help too.

In reply to dculberson :

I tried that a bit when I had it jacked up off the ground to check the brakes and didn't notice much of anything, but I'll need to do it again with each individual wheel as well as trying to see if I can get any movement with the suspension jacked up a bit (jack up the control arm so the arms are more in normal driving position).

Jacking by the control arms means you won't be able to tell if the inner bushings are worn. Shouldn't be an issue though as I bet they're not the problem.