Muscle Mustangs & Fast FordsHow To Drivetrain
1996 Ford Mustang G-Force Racing Transmission - Stick-Shift Superstar
If You're Shifting Serious Horsepower, It May Be Time To Step Up Your Gearbox To A Race-Bred Five-Speed From G-Force.
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.
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.
The one drawback to the GF-5R versus traditional stock-style transmissions is the initial investment. The base clutch-assisted unit runs $5,850 just for the transmission. As Papitto explained to us, though, racing competitively with a 700hp machine is costly; it just depends when and where you spend the money. It's better to spend it once and get the best parts than to break substandard parts over and over. If you plan to race or apply big power, you will eventually get the good parts-it's just a matter of when you buy them.
"I've blown up four or five street-style trans-missions, including three modified TKO transmis-sions in one season," Papitto says. "That's about $2,800 per transmission, and that's not even figuring in the cost of entering the event and traveling to and from it just to go out of compe-tition in the first round."
"Al was really trying to put way too much power through the trans he was using," says Mike Long of G-Force. "The TKO wasn't made to handle that kind of power or be shifted that high. He was also using a TKO with the Fifth gear removed, and he wanted to try our five-speed."
More than 700 hp at the crank is what Papitto's mean machine puts out. Add in 8,100-rpm shifts in a 3,000-pound-plus car, and you can imagine the abuse going on in the transmission tunnel.
After ordering his GF-5R, Papitto dropped off his ride and the new gearbox in the capable hands of Dick Arbitelle of Dick Arbitelle Performance in Vero Beach. Though Arbitelle usually restores vintage musclecars, Papitto told us his craftsman-ship is excellent and that he's meticulous-just the guy for a custom installation like this.
Papitto was able to reuse the Lakewood safety bellhousing from his TKO unit, as well as the McLeod Soft-Lok pressure plate (PN 4968-00). A new clutch disc was needed to match up to the new input shaft's different spline count, and Papitto had Precision Shaft Technologies in Clearwater, Florida, spin up a new driveshaft that uses the G-Force hardened slip yoke. A little sheetmetal cutting and relocation of the crossmember was all that was needed to make this install complete.
What's more important is how the car performed on the track. The Cobra's previous best was a 9.8 at 138 mph, and with the GF-5R, the snake has slithered to a 9.29 at 143 mph.
"I used to run the car with one turn in the clutch adjustment," Papitto says. "I could barely move it around the pits, but that's the only way the trans would survive. With the G-Force, I can put so many turns in it that I've almost put the car on the bumper a few times." The other benefit from this swap is that Papitto has already put 60 passes on the transmission without one problem. "I haven't done anything but put gas in it," he says.