The new output seal finally came in, and I had to rush to get it installed before dinner with my wife. Luckily, it’s a pretty simple job — unbolt the driveshaft, pull the old seal, tap the new one in, and call it done. I actually used part of my ball joint press to seat it perfectly, and so far, not a single drop of fluid since. Small win.

While the driveshaft was out, I figured I’d take another shot at adjusting the suspension angles… but my efforts fell short. On the way to dinner, it shook like I hadn’t touched it at all. Look, I swear I’m not an idiot, but this whole driveshaft geometry thing has been humbling. Which way is up, what’s parallel to what — I’ve never felt so lost, and geometry used to be my best subject.

So there I was, at dinner, scrolling through diagrams and angle calculators on my phone while my wife looked increasingly unimpressed. But — it paid off. Something clicked when we got home. I went back outside, flashlight in one hand and fighting off mosquitoes with the other, to make what I hoped would finally be the right adjustments.

And you know what? It worked. The constant vibration I’ve been chasing for weeks is finally gone. For anyone else stumbling across this in frustration, here’s what actually fixed it for me:

• Zero the gauge on the frame rail.

  • Forget what you’ve read elsewhere — the frame rail is the only solid, consistent reference point on the vehicle. Use that as your zero point. Make sure to remember exactly where you zeroed it, because you’ll likely need to re-zero later.

• Measure the transmission (driver) side angle.

  • Keep the gauge in the same orientation — don’t flip it or rotate it — and record that number.

• Measure the driveshaft, then the axle side.

• Once you have all three numbers, you can plug them into an angle calculator (or do the math yourself).

  • Shaft – Driver = X

  • Driven – Shaft = Y

  • X and Y should be within 1 degree of each other.

  • My first readings were way off:

  • 9.3 – 3.3 = 6

  • 12.3 – 9.3 = 3

  • So, yeah — 6 and 3 is not great.

• Adjust the upper rear control arms.

  • Extend them to increase the rear angle. This is where things can get tricky. I had the rear end jacked up from the axle, so every time I changed the angle, my “zero” point shifted because the whole vehicle moved. That means my 3.3° on the transmission side actually became 3.6°, and the driveshaft angle flattened out as the rear axle rotated.

  • So, every adjustment required me to re-zero, re-check, and re-calculate — over and over — until everything lined up.

After all that, the vibration was mostly gone, but there was still a little shimmy now and then. At that point, I was convinced it had to be the tires.

So, back to Discount Tire I went — full circle. I explained everything I’d been through and asked for a full printout of each tire’s specs and roundness so I could figure out if any were out of spec. Unfortunately, they didn’t give me any of that. The tech just said they “did the best they could” and “had to add a lot of weight.”

To me, that sounds like bad tires. I’ll probably take them to another shop soon to confirm, but for now, it’s way better — and finally, an enjoyable drive without the steering wheel trying to shake itself off.