Kento

A "dog engagement" transmission uses "dogs" forged/cut into the gear rings themselves (instead of synchromesh rings attached to the gear face) to synchronize the gears so they'll mesh together properly. A "dogbox" can actually change gears under a slight load, because the dog engagement lugs are far stouter than any synchromesh ring; this means you can shift without the clutch by momentarily cutting power (backing off the throttle or cutting ignition), but if the transmission isn't sequential (you must shift through the gears in order like the WRC cars, you can't jump from 1st to 3rd, etc.), it's a bit hard on the shift mechanism components. Dogbox gears are usually "straight cut", while standard synchromesh transmission gears are "helical" (cut at an angle like the Trust/Greddy gears in the previous photo) ; straight cut gears are much stronger, but they are incredibly noisy (as is the shift mechanism), which is why they're almost never used on production automobiles.

You obviously still need a clutch to engage first gear so that the engine won't stall.

sub9lulu

iTrader: (7)

o i c
well i actaully just want to learn a little bit more on that
i dont think my wallet is ready to dump 6000 in a tranny yet and its kinda pointless for me to use dogbox on the street

OneRotor

iTrader: (3)

as far as i know, the only WRC car that currently uses a dogbox is the 2005 (i think the 2005 is the really goofy looking one, i don't get SPEED here at school so i'm not sure of the year) Mitsubishi Evo. they didn't want the extra complexity of the electro-pneumatic or electro-hydraulic trannys while they are sorting out all the bugs on their new car. the rest of them use either an electro-pneumatic or electro-hydraulic sequential manual, much like a F1 gearbox. up until, and through the 2003 season, all SCCA Pro Rally cars used dogboxes, and they were allowed to change to WRC/F1 style sequential boxes for the 2004 season, but i doubt that many teams wasted their money since SCCA ProRally is done now that the 2004 season is over with. i'm pretty sure that all sport bikes, along with cruisers, use dogboxes.

Hellspawn

I love my 6-speed tranny

Kento

Should've been more specific, I meant to use only the "sequential" example with regards to the WRC transmissions. Actually, the "electro-pneumatic/hydraulic" term only applies to the actuation of the shift mechanism in the transmission; the gearsets themselves still use either a variation of the synchromesh or dog engagement. And yes, all motorcycles use a sequential dogbox.

RX7 Japan

Yeah, 6 speed would be cool here in Europe. I'm here in Germany now and boy do they drive fast.
BTW, said it would be cool to have, no way I could afford one especially after forking out $4100 for a rebuilt engine.

Neakor

i dont think its worth the price,but a 6 speed tanny is better than the stock especially with a huge single which has a hell lag.

Spirit_Rotary_7

http://www.rotaryextreme.com/fddrivetrain.html