Really trying to understand where all this crap about marking the propshaft in relation to the differential/transfer case flanges before removal came from.

Pretty much every guide, and every forum warrior repeats the same thing yet every driveline shop I've ever spoken to does NOT balance a propshaft with the flange.

Scribing the propshaft if you plan on taking it apart at the splip joint makes sense. I've yet to find one good reason to scribe/align the propshaft to the flange.

Anyone care to shed some light?

 

I never mark them in relation to the output and input flanges on the transfer case and diff (even though the shop manual says to). I do mark all parts of the propshaft in relation to each other. Sometimes they don't need re-balancing if they go back together in the same orientation.

 

What does it hurt to mark them before removal?
If you dont want to then dont, if someone else does who cares?
I always do, it gives me piece of mind and to me that is worth the 60 sec. it takes to do it.
Each to their own.

 

My point is, everyone preaches it yet so far noone has ever been able to answer why. The way people repeat what they read on a forum as Engineering gosspel drives me nuts.

I feel this is one of those "internet mechanic" myths that has no bases. I'm seeing if anyone can prove otherwise.

 

There is a little tab welded on one side of the shaft to balance it, the marking is to help put it back in the same orientation. They claim if it is unbalanced it will vibrate, or so they claim.

I changed my rear shaft out to a 98 version and lined the tab on the second one same as the first one was. No vibration, then it may have just been luck. There are four possible ways to put it on same as it was or staggered by 90,180, or 270 degrees.

 

You will never get a answer that you will be satisfied with on how it got started.

 

Which still makes no sense to me...

Say you take your unmodified bone stock rover into the dealership. Yep you're a dumbass, didn't clear that rock and have bent your rear propshaft.

They order up a new one, it's either pre-balanced or they balance it. Never once does that new shaft get balanced/mated to the flange. So what difference would the shaft/flange orientation make?

 

If I find a technical reason for it, then sure I will. So far I've yet to ever see one other then the ever so technical "because" argument.

 

Didn't have anything better to do than argue I guess.

You could do an experiment and rotate yours 90 degree and tset drive it and repeat for each position to either prove or disprove the theory that it does or does not matter.

Then you would have real life data to establish the true nature of the rotational balance theorum of the Land Rover Driveshaft. The demonstrated performance data, after enough of it is collected to establish whether a trend exist, is much better than trying to theorize or explain why or why not one believes that a difference indeed exists.

How many different vehicles and how many different driveshafts are required to truely establish a pattern is debatable. The more data points collected, the closer the true picture will be reflected in the conclusions of the study.

Savannah, what do you think? How many data points would be needed to establish validity?

 

Noones arguing. I love the internet. You can't question anything without it being personal.

It's a simple question. I've got the same question going on a few of my forums and noone can answer it with any technical reason. It's purely out of curiosity as I see it so often, I figured surely I'm missing something not everyone else.. But so far it seems to be just another internet myth.

I can see the benefit of scribing a shaft that you cant remove in one piece. I've personally never seen one of those on any vehicle though.