Left front vibration at highway speeds

Trainmaster said:

Sorry to hear that didn't help. I assume the tie rod ends were checked?

And have you checked your drive shaft universal joints? They're a cause of vibration, maybe not left front but sometimes it's difficult to pinpoint to source.

You can try removing the front driveshaft and seeing if the vibration continues...

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I did check the tie rod ends and they’re tight. I haven’t checked the drive shafts yet but that’s an option. The vibration isn’t as pronounced as it was after I did the work on the front, which is why I’m leaning toward the CV axle before the ball joints.

Update: I checked the lower balljoints using FordTecMakeYouLoco's prybar method and both are solid, so really leaning toward the LF CV axle. It looks good from the outside (no torn boots, spins freely when IWEs are engaged) wondering if any damage could've been done when the LF IWE wasn't engaging fully before I replaced them and the vacuum lines.

Any other thoughts on this? Only other options I'm considering are UCA & LCA replacement.

At this point I'd remove the front driveshaft and see if it changes. If that didn't help, I'd pull the hub which would let me inequitably check all the ball joints, rod ends and control arm bushings. Then I'd be able to pull the front axles and see if they are okay.

I don't know what else you can do at this point if all the work you described was actually done. Anyone have another idea?

Trainmaster said:

At this point I'd remove the front driveshaft and see if it changes. If that didn't help, I'd pull the hub which would let me inequitably check all the ball joints, rod ends and control arm bushings. Then I'd be able to pull the front axles and see if they are okay.

I don't know what else you can do at this point if all the work you described was actually done. Anyone have another idea?

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Not sure how pulling the front driveshaft will help since I’m experiencing this in 2H. If you can explain that to me, I’m open to trying it.

I’m going to do the UCAs, LCAs, and sway bar bushings since they’re most likely worn out at 168k (hollow sounding noises and alignment is still off) then realign and rebalance before rediagnosing. Steering is tight so not doing tie rod ends right now.

I didn't think you mentioned that this was doing this in 2H.

Update after my Thanksgiving road trip to FLL (~2k miles road trip). Vibration is still present, surfaces around 70 mph and is most pronounced 75-80 mph. Vibration subsides when under load (acceleration, climbing) and when turning, gets worse when decelerating with cruise control (engine slowing) and when going straight. Over 80 it subsides but in general feels a bit rougher. Tires are riding smoothly at all speeds. Minimal vibration through steering wheel, no rocking or shuddering of the wheel.

Only parts I haven't replaced yet are tie rods (inner & outer) so I'm game to do that if needed. Steering feels lighter than in the past, but no play or drift in the system. Truck is aligned to factory specs per Firestone print out.