Question: What is a Traction-Lok differential and how will it help me?
Answer: This is a great question! A differential upgrade is practically a requirement for anyone looking to tear it up at the strip, so let’s start with some basics: the differential (aka “rear end”, “rear”, or “pumpkin”) is that roundish thing that sits between your rear axles; it’s responsible for transferring power from the driveshaft to the rear wheels and allowing the wheels to spin at different speeds when going around turns. With a job that important it’s easy to see why having a bullet-proof rear is so crucial for serious racers.
LSD and You…
Drugs are bad, mmkay? Just kidding, we won’t be discussing hallucinogens today. Mustangs came with either an open or a limited-slip differential from the factory. Open (aka Conventional) differentials are quite common and are responsible for peg-leg (one-wheeled) burnouts due to their “path of least resistance” setup. In an open differential, when one wheel starts to slip, all available torque goes to that wheel. If you’ve ever been stuck in a slippery spot with an open differential, you know how frustrating this can be. Limited-slip differentials (LSDs) have ingeniously overcome this problem by using clutches and springs. Before one wheel can spin faster than the other, it must first overpower the clutches, making it more difficult for just one wheel to lose traction; forcing both wheels to spin allows you to put more power to the ground as well. There are several types of LSDs out there and every manufacturer has their own nickname – Ford’s is “Traction-Lok” (aka T-Lok or Trac-Lok).
Pumping Up Your Pumpkin
There are a couple options for beefing up your stock 8.8” LSD – you can rebuild your existing diff with a Ford Racing Carbon Rebuild Kit which has the same heavy-duty internals as the Cobra rears; or you can replace the entire carrier with an aftermarket unit like the Ford Racing 31-Spline Traction-LOK differential. Keep in mind that the “31-Spline” part refers to the axles, so your factory 28-spline axles will have to be replaced. More splines = more power potential – 31 spline axles can handle significantly more power than the factory 28s, so if you intend to put serious power down you’ll definitely want to invest in a set. For my fellow V6 owners there are 7.5” Traction-LOK differentials available, although if your six is pushing serious power, an 8.8” swap is also an option.
So to recap: by evenly distributing torque between the rear wheels using clutches and springs, a limited-slip differential can help you hook-up at the track and enhance traction in less-than-ideal weather conditions*. Here at AM we offer products to improve your existing LSD, aftermarket units that will be a great improvement over stock, and the know-how to guide you to the right mods for your performance goals.
*DISCLAIMER: No differential or modification thereof could have allowed you to drive safely in the 2-3 feet of snow we received here in the northeast recently… although we did not try adding fairy dust to the differential fluid.