Drive shaft length!?

I've tried searching but getting mixed results. For the last two days I've been chasing down a vibration. I bought my truck with aftermarket wheels and dry rotted tires. First thing I did was replace the wheels with factory 2014 Tacoma Sport 17" wheels and brand new 265/70R17 AT tires. Had the tires balanced and road forced and felt a vibration in the rear at 60mph. I searched and found thousands of threads about vibration and jumped on the first two immediately. The two being lug centric vs hub centric (haweka adapter and so on) I have an appointment at the dealership Friday to have them properly balanced but for shits and giggles I decided to have the driveshaft checked since the truck has 299,512 miles on it! The very first thing I was told was that my driveshaft was too short by Carolina Driveline, a very reputable and knowledgeable driveline business. I've never replaced it, the guy I bought it from says he hasn't replaced it either. The only other person that owned the truck was an older gentleman that bought it brand new and put the first 285k miles on it with services done like clockwork. He is not available for questioning. It is a 2002 taco reg cab 4x4 all stock so it has a one piece factory toyota driveshaft with a standard ujoint at the rear diff and a double cardigan joint at the transfer case. My question is this: Why would my driveshaft be too short? And if it was replaced by a Junkyard part or even a new part, what would it have been removed from? Are automatic driveshafts shorter? I was told the driveshaft that is installed is too short judging by the wear marks on the slip yoke and measurements taken from the truck. What is the factory driveshaft length for a 2002 taco reg cab 4x4 all stock?

 

That sounds like BS!?!? I'll put a tape on mine for ya if I get a chance today!

 

Awesome, I'd appreciate it man! I doubt very seriously that they are trying screw me, they're a family owned business and have always taken good care if us and they were just as surprised as me. When I measure from face to face (transfer case to rear diff) I get 47.5". My shaft was only around 42.5" from face to face collapsed. It is almost pulled off the slipe yoke when installed so its definitely too short by regular standards unless it's just a Toyota thing. That's what I'm trying to figure out.