Apparently I am an ignorant SOB, according to a man selling drive shafts for over 20 years. Let me explain:

Got a used drive shaft from a junk yard and slapped it on. Still had a vibration around 52 so I took it to my local very experienced, straight shooting, trust-able shop and they informed me that the differential and transfer case seem fine, but it looks like the drive shaft was pulled apart and never marked so it is probably now out of balance. I know in my Haynes manual it claims to mark the shaft and yoke before separating because if you put it back together differently it is now out of balance. I asked two other mechanics and they said the same thing. I offer this bit of advice to the fat arse behind the counter and he claims that I could not convince him that is true as he has been selling these for over 20 years and never heard of that. He then comes around the corner and tries telling me that on Chevy's the yoke will twist lock into place so it will no longer freely move. Shouldn't it have the freedom to move considering it is connecting to an active suspension? So basically, now this fat mf tells me I am screwed and he will be glad to replace it with another, but he will always pull the yoke off of the shaft to inspect it and put it back on without marking it.

So what's the deal on this, does it make a difference or not?

 

Yes, proper driveshaft "phasing" is important and you can do it yourself:

http://www.4crawler.com/4x4/CheapTri....shtml#Phasing

And check the alignment while you are at it. If the pinion flange angle is not correct for the type of shaft, you'll have vibration no matter how good the shaft is:

http://www.4crawler.com/4x4/CheapTri...l#Measurements

 

When I just did my u-joints I cleaned the drive shaft up real nice with a bunch of engine cleaner, that way I could mark it and not have it rub off. Well guess what I found under all of that grease and grim. The original factory markings, they were yellow and pink and were at every connection. Try and clean it up and look for the marks. They did not come off with the cleaner, as long as you don't scrub just wipe and spray. they did come off with "Brake Cleaner" as an FYI.
Hope that helps.

 

Yup, I also just replaced my U joints, and I marked it all up. My dad has been a mechanic on big rigs for 18 years, so he helped me do it.

 

So I'm not completely stupid...
Thanks for the assurance and info on how to phase it. I just can't still believe he tried to tell me it makes no difference...

 

Some driveshafts are different than the Toyota 4WD shafts. Some have the slip yoke inside the transmission or t-case output and the rest of the shaft between the u-joints is all one piece (2WD Toyotas are this style as are Jeeps). So on those type shafts, phasing is not even an issue excpet for the shop welding up the shaft in the first place. If the shaft uses a CV joint on one end, phasing is also not an issue.

 

yup... but if there is a slip yoke on it, don't you think it should actually "slip"? Common sense isn't something we all posses as proven by this fat arse...

 

Yes, almost all driveshafts will have a slip yoke someplace and the slip yoke must slip in and out to accomodate length changes.