Dog Box Transmission
People love to go fast. It's in the human DNA somewhere right around the "go fast" gene. Some enjoy the occasional stop light grand prix in an attempt to see who can reach 50 MPH first. Others take speed to a completely different level. These are the guys striving to put down times faster than Michael Phelps on steroids. Super fast cars do more than register high trap speeds; they destroy various components of a car, especially the transmission. Even Honda's unprecedented reputation of strength and reliability cannot escape the consequences of cars with insane amounts of horsepower.
Honda, with its forward thinking, has presented enthusiasts with a number of incredible motors. The not so recent K motor has allowed Hondas to further lower their elapsed times, but not without indirectly destroying a few transmissions along the way. Any naturally aspirated Honda producing at least 300 WHP will typically start breaking transmission pieces. In naturally aspirated cars, second gear tends to be sacrificial lamb due to high revs placing a lot of stress on the transmission. For turbo powered Hondas, breakage begins around 500 WHP. With boost, second and fourth gear often give-out under excessive boost loads.
Transmission synchros are also a weak link for both NA and boosted cars. Some racers shift so fast that the stock K transmission doesn't have enough time to properly engage the next gear, causing severe and irreversible damage. These extreme shifts grind the steel synchros against the steel engagement teeth on the gear. Steel grinding on steel can be catastrophic, often ending the life of a transmission. Too much stress can even cause the aluminum transmission casing to explode, sending many racers home packing. Grinding gears is kind of like going into an Irish pub and telling the owner he should call it a United Kingdom pub: something is bound to break. For extreme shifting duties, an alternative transmission may be needed. This is where the Dog Box comes in.
 Typical characteristics of...  Typical characteristics of dog teeth gears. Notice the straight cut design. |  Dog Box mainshaft on top;...  Dog Box mainshaft on top; stock mainshaft on bottom. |  A little Torco MPZ spray lube...  A little Torco MPZ spray lube never hurt. Although it will increase protection during the break-in period, it will not get rid of excessive arm hair. |
Stock K transmissions have lots of gear teeth that are angled for smother shifting. They also have tons of tiny parts, all of which are used to uphold Honda's legacy of durability and strength. Dog Box transmissions have fewer teeth, but they are larger and much straighter. They use far fewer parts than OEM transmissions while still retaining reliability. These gears are made to handle fast shifts in high horse powered vehicles. To some extent, the straight-teeth design creates a unique, almost whining sound inside the car. Not all Dog Box transmissions sound the same, but for the majority, the gears produce a sound similar to the noise a stock reverse gear makes when in use. Less parts and dog teeth make this upgrade a highly effective item for any serious racer.
Although these transmissions can be driven on the street, they're intended for racing. In order to shift, the user must unload a little torque to ensure the dog teeth are not lined up. This can be done by tapping the clutch or letting off the gas similar to shifting a stock transmission. The majority of racers with bigger budgets utilize a strain gauge to unload power. A strain gauge sends a signal to the ECU to stop the ignition which in turn unloads power long enough for a super quick shift. Though these tranny's are strong, that doesn't mean they can't be improperly used. That's why caution is strongly urged in using this transmission for daily driving. Grocery duties are better left to a backup beater.
Most racers with cars producing over 300 WHP opt for a Dog Box after they get tired of replacing their stock transmission. Repeatedly replacing transmissions and the parts involved is time consuming and costly. A few blown transmissions resulting in "Did Not Finish" scores and several thousand dollars in repair costs can entice even the most thrifty competitor.
 Dog teeth second gear on left;...  Dog teeth second gear on left; stock second gear on right. |  Stock mainshaft third gear...  Stock mainshaft third gear on left, Dog Box mainshaft third gear on right. |  Dog teeth fourth gear on left;...  Dog teeth fourth gear on left; stock fourth gear on right. |