The devil is in the details when it comes to buttoning up a drivetrain package. If a build includes significant changes to the engine, transmission, or rear end, chances are that the factory driveshaft is a hair too long or a shade too short. Rather than playing a guess-a-shaft game, it’s imperative to get one that’s the proper length and circumvent a horrendous array of potential catastrophes.

Robert Hall of American Powertrain put together a quick video to show the correct measurement methods necessary for a trouble-free TREMEC stick shift swap. The first step is to make sure the full weight of the vehicle is on the suspension. A two-post lift won’t do since it allows rear suspension components to sag and throw off dimensions. “Start your measurement at the machined surface at the rear of the tailhousing. From there, go to the face of the flange on the differential. This will put you in the center of the U-joint,” Robert says. The angle of both the differential and the transmission also play a part in American Powertrain’s calculations.

“Once you’ve established the length of your driveshaft, the next thing to do is find out what size of U-joint you need.” Standard dimensions are the overall length as well as cap diameter. The last step is deciding on driveshaft material. American Powertrain offers drawn-over-madrel (DOM), aluminum, and carbon fiber shafts. To find out which is best for you, give their experts a call at (931) 646-4836.