Sequential Gearbox Rebuilds
Flat-shift, no clutch, no lift. We rebuild and maintain sequential and dog-engagement gearboxes so the next gear is always there when your hand asks for it.
A sequential box is the difference between thinking about shifting and just shifting. Straight-cut, dog-engaged gears let you bang the next ratio in flat with no clutch and no lift — but only while the dogs, selector drum and shift mechanism are in spec. The moment engagement gets lazy you start missing gears at exactly the wrong moment.
We strip, inspect, rebuild and re-ratio sequential and dog-pattern gearboxes for gravel, tarmac and dirt-track use. Everything that comes apart is measured, crack-tested and logged so you know exactly what state your driveline is in before the season starts.
Strip, measure, and tell you the truth
Every rebuild begins with a full teardown. We measure dog clearances, check the selector drum and forks for wear, inspect bearings and shafts, and crack-test the highly stressed parts. You get a written report — not a vague "it needed a freshen up" — so you can budget around the parts that are genuinely tired versus the ones with seasons left in them.
Worn dogs are the usual culprit behind missed and popped-out shifts. We re-cut or replace dog rings, set the correct undercut, and reshim the cluster so engagement is positive without being notchy. Done properly, the box bites the next gear cleanly and stays in it under full load.
Ratios matched to the stage, not the catalogue
The right ratio set depends on the surface, the typical stage speeds and your engine's power band. A tight, twisty gravel rally wants a very different stack to an open tarmac event. We talk through your calendar and engine map, then specify ratios that keep you in the meat of the torque curve between the corners that matter.
We also handle final-drive changes, billet selector upgrades and shift-cut wiring so the gearbox plays nicely with your ECU's flat-shift strategy. The goal is a driveline that disappears — you stop managing it and start using it.
What's included
- Full teardown, inspection and written report
- Dog re-cut / replacement and reshim
- Selector drum, fork and bearing service
- Crack-testing of shafts and high-load gears
- Custom ratio and final-drive selection
- Flat-shift / shift-cut wiring integration
- Run-in and pre-event setup advice
