Is your Stang ready for the...
Is your Stang ready for the track? G-Force has the transmission to get you to the finish line every time.
One of the most enticing aspects of the Mustang hobby is getting behind the wheel and executing perfect gear changes manually. Whether you do this in a heel-and-toe fashion while downshifting for a corner or nailing a series of foot-through-the-floorboard powershifts, it can be a great driving experience when you get it right.
Depending on how much you race or how hard you work your Mustang, the factory gearbox may not be up to the task, especially if you've upped the available horsepower and torque. Add a few extra rpm and you can easily kill the stock transmission. It may be time to step up to something that can stand a bit more g-force. In this case, we did so with a G-Force Racing Transmissions GF-5R, which is a race-style trans that can be had with a pistol-grip V-Gate shifter. This transmission features face-tooth gear engagement and no Overdrive, but it's ultra-strong and can improve the elapsed time and fun factor of any stick-shift machine.
While manual transmissions in Mustangs have always been available, late-model 5.0 Mustangs with their T5 five-speed gearboxes have offered the fun of manually shifting your transmission while providing an Overdrive gear to bring down the cruising revs-definitely a case of having your cake and eating it, too.
Over the course of its lifespan, the T5 evolved and could handle a good deal of power, but its relatively small internals eventually limited just how much power you could throw at one, or how many powershifts it would tolerate. A clean sheet of paper provided the Mustang with the T45 five-speed manual in 1996-a questionable unit that offered larger internal parts but was often broken when driven aggressively. It was eventually replaced in the middle of the '01 model year by the T-3650, when the Mustang finally got another stout stick shift from the factory. The T-3650 continues to be the choice for 4.6L Mustangs today. As good a trans as the 3650 is, it-like the others before it- has limits, as it always seems like the ability to add horsepower is two steps ahead of what the rest of the drivetrain can handle.
The GF-5R is a true five-speed...
The GF-5R is a true five-speed transmission, built to endure the rigors of race duty. The stout but limited Tremec TKO transmission in the background is what car owner Al Papitto was using to run 9.8-second elapsed times in the quarter-mile. Unfortunately, it would break on occasion, and knowing that this was a track car, Papitto obviously needed something a bit more reliable.
Numerous aftermarket companies offer upgrades for all of these transmissions that can allow them to handle two to three times the stock engine output. Confined in the same-size trans-mission case, however, those high-performance parts can handle only so much. If you've found yourself breaking a highly modified T5, T45, or T-3650, then you may need to step up to an entirely new transmission that was designed with optimum performance as its main goal, rather than smooth shifts and reduced noise, vibration, and harshness. That's where Vero Beach, Florida's Al Papitto found himself with his modular-powered Mustang.
Papitto and his Boss 330 Racing shop have been at the forefront of modular engine technology for several years now, and his bright-red '96 Cobra is a shining example of just what these overhead-cam engines can do. Sporting a Ford GT-based 334ci block with Four-Valve cylinder heads, this missile offers up a 700-plus-horsepower warhead that has killed competitors and components alike.
Papitto went the usual route, starting with the Cobra's stock T45 transmission, and then going to a built T5 box, a T45, a T56, and even a 4R70W that ate up four converters. Eventually, he ended up using a pro-shifted Tremec TKO transmission with face-tooth or dog-ring gear engagement. These lasted the longest, but failure was always on the horizon, and pulling trans-missions in and out gets old, especially when you're not getting paid to do it. Papitto also uses the car to compete at various NMRA drag races, and you don't make it to the finals if your parts are breaking. That led to his conversation with Mike Long of G-Force Racing Transmissions.
Based out of Cleona, Pennsylvania, G-Force offers all sorts of high-performance manual transmissions, from modified T5 five-speeds, to six-speeds, to full-on NHRA/IHRA Pro Stock clutchless gearboxes. Papitto had his sights set on the GF-5R five-speed gearbox for his Cobra. Available as a clutchless or clutch-assisted unit, the GF-5R can be assembled with a virtually endless choice of gear-ratio configurations, and the folks at G-Force can help you pick out the right ones for your application. It also features wide gears for strength and a hand-cuff system that keeps the mainshaft and the cluster shaft from spreading under load. This, in turn, keeps the gears engaged properly, and that helps prevent breakage. The GF-5R also sports rollerized internals, so you benefit from reduced friction, and that brings lower track times. For many years, Editor Evan Smith has used a GF-5R with great success in his Stock Eliminator ride, as have NMRA Hot Street racers like Charlie Booze Jr. and Bangin' Bob Hanlon.
 Papitto sprung for the magnesium...  Papitto sprung for the magnesium tailshaft section to save a little weight. The transmission case itself can be had in magnesium for an extra $350. |  G-Force puts the gear ratios...  G-Force puts the gear ratios and torque specs right on the case for easy identification. Just looking at the side of the GF-5R tells you this is one beefy piece of hardware. |  A steel bearing retainer is...  A steel bearing retainer is employed, as is an 18-spline input shaft. |
 The GF-5R was equipped with...  The GF-5R was equipped with this Long shifter. It's a V-Gate-style gear changer, which means all you have to do is row it back and forth, and it finds the correct gear for you. No Third-Gear mystery angle here. Papitto explained that you'll most likely want to cut the floorpan to allow easy removal of the gearbox with the shifter attached, as proper shifter adjustment is extremely critical, and removing the linkage will force you to repeat the intricate process. |  Papitto was able to reuse...  Papitto was able to reuse the McLeod Soft-Lock clutch setup he previously employed. He just needed to get a different clutch disc to match up with the GF-5R's Chrysler 18-spline input shaft. |  The Lakewood safety clutch...  The Lakewood safety clutch housing from the TKO was reused (PN 15230). Papitto mentioned that the clutch fork needed to be notched to clear the pressure plate. |