Modern transmission swaps into older vehicles are all of the rage these days, and there’s no need for explanations as to why. The availability of more gears, stronger units and the capability to become more competitive and more efficient on the road just adds to the appeal.
During a recent visit to Tennessee with Project Redrum, we teamed up with American Powertrain and used our project ’84 Trans Am for their brand new line of direct-fit, 3rd-gen manual transmission swap kits. However, one of the formalities commonly associated with swapping out one transmission for another, is the fact that you usually have to extended or shorten the length of the driveshaft to fit, depending on application.
This involves measuring the space between the transmission tail housing, and the center of the yoke attached to the rear axle. You’ll also have to measure the width of the U-joint and the size of the caps, to ensure proper fitment. As a bonus, American Powertrain actually has a chart in their instruction manual which show you what U-joint you need, based on your measurements.
It’s typically much easier and highly-reccomended to produce accurate measurements if you have a drive-on lift or two sets of ramps, to take the weight the car off of the suspension. The lat thing you’ll want is to end up with a driveshaft that’s too long, or worse, too short!
Rick Seitz is the owner and founder of GMEFI Magazine, and has a true love and passion for all vehicles. When he isn’t tuning, testing, or competing with the brand’s current crop of project vehicles, he’s busy tinkering and planning the next modifications for his own cars.