[grivera]

That isn’t the case here - I have no issue buying parts but also diagnose in the process- it’s just the way I operate. Some “throw” parts at everything. I like to learn in the process.

When I get some time I plan to reconfirm the tailshaft and pinion angles then order a new 3.5” driveshaft.

[Keith Seymore]

Right; understood - I meant "other guys".

K

[HWYSTR455]

Critical speed is pretty much all you need to know aside from balance & construction, and you always shoot higher than the 'average'.

Modern Driveline has a good outline:

https://www.moderndriveline.com/a-li...out-vibration/

But when it comes to age, or unknown origin, you pretty much know it needs to be replaced. It's pointless to 'fix' an 'old' driveshaft, especially if it looks like it's OE.

Once you replace it, then YOU know it's age & origin, and type of construction, THEN you can go forward with fixing/adjusting if need be.


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[HWYSTR455]

Another tip, never re-use OE shaft ends or slip yokes, period. Only re-use ends/slip if YOU purchased it originally and is of quality construction.

Same with u-joints, but honestly, if you're going thru a shaft trying to diag an issue, replace.

Differential yokes & caps are another problem, but same principals apply. They do wear out/break/fail.


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