Both of my seals were leaking; I'm fairly handy, but after quite some time with the inner seal, I gave up and bought the new assembly. I'll never go down that O-ring hole again.
Got it replaced 2 nights ago. Easy peasy. No leaks.
Added in a Lutz Auto Speedometer Calibration Module I've had for 3+ years.
I'm an idiot for not installing it sooner. I highly recommend it. Do the math right, and mine is now GPS accurate from 10-75+ mph right on the money. Additional benefit is the corrected odometer, which on my first 24.3 mile, GPS neasured loop, was off by 1/10th of a mile, so it's now accurate to 0.2% or so.
Seeing your speedo needle climb correctly, makes you think that your Cruiser, isn't quite as slow as previously thought, too.