B-Series Final Drive Install - Geared Up - Wrenchin'

Yank the tranny from the car,...        read full caption Yank the tranny from the car, set it on a workbench, and begin by removing the backup light switch, the two set screws-each with their respective springs and steel balls-and the transmission hanger bracket. Remove the reverse idler gearshaft bolt with a 14mm wrench and plan on replacing its washer before you're done. Remove all 16 bolts that attach the transmission housing to the clutch housing in a crisscross pattern. Unbolt the 32mm sealing bolt, expand the exposed countershaft's ball bearing snap ring with a pair of snap ring pliers, and pull it out of the groove. Although it's not shown here, it's best to place the transmission clutch-side down on a couple of blocks of wood so as to avoid damaging anything.

Tap the case with a rubber...        read full caption Tap the case with a rubber mallet and separate the transmission housing from the clutch housing with a pry bar. Be careful not to mar up either surface.

Locate the transmission case's...        read full caption Locate the transmission case's magnetic tray and clean any metal shavings and debris from it. Debris like this is normal and is what the tray is there for, so don't freak out.

Gearing changes everything. It can make a slow car feel quick and a quick car feel slow. Honda engines typically have narrow rpm ranges where both horsepower and torque are at their maximum. The transmission's job is to allow for near seamless changes between the engine and the car's wheels as vehicle speeds change. Shifting allows the engine to stay below its redline but remain close to its sweet spot. Ideally, a transmission would have an infinite number of gears, each of which would keep the engine operating at its most ideal rpm, but unless you're talking about continuously variable transmissions (CVT), which aren't exactly suited for sizeable amounts of torque, then gearing becomes really important.

A typical B-series Honda transmission has two main shafts inside of it that mesh with one another via sets of gears -the mainshaft, also referred to as the input shaft, and the countershaft, or output shaft. Both are fitted with a series of gears, synchros, and bearings, among other important parts. The mainshaft is connected to the engine through the clutch and spins however fast the engine spins-it has no choice. If you have a five-speed transmission, then up to five different gears are applied, which results in five different rpm values at the countershaft, ultimately translating into what the drive wheel(s) see. Gears simply act as torque multipliers and help make the best use of the engine's available torque, whether you're accelerating from a stop or cruising down a hill. For example, a 1.360:1 gear ratio simply means it takes 1.36 mainshaft turns for every output shaft turn. Gears alter a vehicle's wheel speed and the amount of torque that's applied in relation to the engine's speed and torque values, but five or six gears planted along these two shafts aren't the only ways to get this done.

A transmission's final drive ratio is just as important as its individual gear ratios. The final drive ratio is the speed of the transmission's countershaft versus the speed of the car's drive wheel(s). Think of it this way: A Honda transmission is always operating using two gears-you've got whatever gear you're in and you've got the final drive gear, aka the ring and pinion gear. Take a late-model GSR transmission with a 1.360:1 Third gear ratio and a 4.400:1 final drive ratio. You've got to multiply these two numbers together to get your effective Third gear ratio of 5.984-the actual gear ratio. This means it takes 5.984 engine revolutions to get the wheel(s) to turn once. Pair one of MFactory's 4.928:1 final drive gears to the GSR gearbox like we did and you'll end up with a 6.70:1 effective Third gear ratio. The higher the final drive ratio, the faster the engine rotates for each rotation of the drive wheel(s). Numbers like these result in better acceleration throughout the entire powerband, in any gear. In other words, the numerically higher final drive gear actually applies more torque at any given speed. It's not uncommon to realize power shifts upwards of 40 whp just by playing with final drive ratios.

Unfasten the change holder...        read full caption Unfasten the change holder assembly's three bolts with a 10mm wrench and remove it from the clutch housing. You'll need to remove the shift piece shaft, shift piece, and the interlock first. Next, pull the mainshaft and countershaft-complete with their shift forks-away from the case, all in one piece. Place each gear set in its own plastic bag. The differential assembly can also be removed from the clutch housing now.

Remove the hardened silicone...        read full caption Remove the hardened silicone from the case with a razor knife, gasket scraper, or wire brush. Don't rush this step because any leftover, hardened silicone will cause the transmission housing to leak once assembled and filled up. Use compressed air to thoroughly rid the gearbox of any silicone remnants.

Remove the reverse change...        read full caption Remove the reverse change holder's two bolts with a 10mm wrench and pull out the reverse idler gear and reverse idler gearshaft and washer.