Education is the word of the day.
Talking with a man from roverlandparts.com this morning about driveshafts (and the vibrations associated with), he passed along some information that suprised me.
It turns out he worked at a Landrover dealer for a number of years and seen countless customers coming in complaining of driveshaft vibrations on their Discoverys. I have such a vibration (as you may already know from my previous post). He is sending me a used driveshaft to try at no charge (!). Well, I'm buying a steering pump from him and he is kind enough to trust me on the shaft as a trial. (nice man I might add, please remember his web site
I have a hunch, my hunch is this: I have a feeling the shaft is not of the right diameter to remain under it's critical speed under normal circumstances. We will see. I'll try the new/used shaft, and if it vibrates, I'll then go through the engineering process and design up a new shaft with the proper diameter for the given lenght and rpms needed based on my 3.54:1 final drive, 18 inch wheels and so on. This formula can be found in most Machinery's Handbooks under "shafting". Been through this once before, years ago, when I changed the final drive from a 2.73 to a 3.73:1 on a Chevy pickup truck. Ended up having a terrible vibration at 80 or so and the final solution was to increase the diameter of the shaft to about 4 inches so to place the critical speed way above what I would attain under normal driving.
The vast majority of you have forgot more about Landrovers than I'll ever know, so if anyone has ran into this or has anything to add, I'm all ears.
Mark