As opposed to using standard synchronizers or Pro-Shifted modifications, G-Force Transmissions has opted for a face-tooth design. While synchronized engagement is ideal for normal street driving and Pro-Shifted modifications were once adequate for drag strip applications, neither is optimum for today's street machines and all-out racecars.
Synchronizers do what their name implies: they synchronize. As a gear lever is moved, the engagement slider pushes three spring-loaded locking struts against a brass synchronizer ring. In turn, the ring is pushed against the speed gear synchro cone. This action accelerates or decelerates the gear, depending on whether it is being upshifted or downshifted, up to the same speed as the slider. Once the speed synchronization is complete, the slider can be pulled easily into engagement with the gear's synchro teeth.
This principle works fine for everyday driving, but can become a nightmare when shifting high engine RPM's. Since the brass ring acts as a "brake", the ability to do its job is dependent on two factors: the weight of the rotating mass and the speed at which it turns. Anyone who has tried power shifting a synchronized transmission at 7000 RPM should now understand why it would not shift!
Rather than having engagement teeth or lugs placed around the circumference of a synchro cone, the face-tooth engagement system has engagement lugs on the adjoining faces of the gear and slider. As the gear lever is moved, the slider moves toward the engagement plate on the face of the gear. When the engagement lugs on the slider find the "windows" between the engagement lugs on the gear, the gear is engaged.
Clutch assisted transmissions can be upshifted and downshifted quickly at ANY engine RPM! Part-throttle shifts can be accomplished without the use of the clutch simply by slightly letting off on the gas, ("blipping" the throttle), while moving the shift handle. Wide-open throttle shifting requires disengaging the clutch just long enough to release the load to engagement lugs. Once you've pulled the shift handle far enough to get out of gear, you don't need the clutch disengaged to engage the next gear. This is a significant improvement over the old Pro-Shifted design engagement. The transmission shifts very similar to a motorcycle in the way it operates inside.
With clutchless gearbox, it isn't necessary to back off the gas pedal or release the clutch even for a split second - when making a gear change.
The GF-5R clutchless transmission utilizes split, spring-loaded sliders. The engagement lugs on each half are ramped on the deceleration side. When the shift lever is pulled into first gear, both slider halves move to engage the first gear faceplate. When the shift lever is moved to the second gear position, only the slider half-facing second gear moves to engage that gear. At this time, both gears are engaged momentarily, but second gear causes the main shaft to increase its rotational speed. This speed difference kicks the first gear side of the slider out of engagement, (hence the need for the ramped engagement lugs). Subsequent gear changes operate the same way. All shifts are made at full throttle, without the use of the clutch, just as they are with a planetary transmission.
The GF-2000 clutchless transmission operates with a slightly different design than that of the GF-5R. The GF-2000 utilizes a different shift fork for every gear, unlike the GF-5R, which uses only 3 shift forks. Because of this, the GF-2000's return springs can be located directly on the shift rails, whereas the GF-5R has split, spring loaded sliders. Again, all shifts can be made at full throttle without using the clutch. Both methods work fine, but the GF-2000's design of having bigger coil springs directly on the shift rails tends to be better for a first-time clutchless driver. For more experience drivers, it doesn't really matter.
Because of the unique engagement system of a clutchless G-Force, the transmission is not suitable for the street and will pop out of gear under deceleration. Since the clutchless G-Force is not a planetary transmission, it doesn't impose the same type of power losses.