The Bert racing two-speed transmission may be quite different from most other units out there, but its simplicity makes it fairly easy to rebuild.
You won't find anything like it on a street car, but the qualities that make a Bert transmission unique also make it nearly perfect for dirt racing. Simplicity is the name of the game here. Bert Transmission's two-speed trannies are all about cutting down on the number of parts involved and reducing rotating weight. Most significantly, the clutch is actually inside the transmission housing, eliminating the typical clutch and throwout bearing assemblies. There are also only two forward gears and a reverse, and the gears themselves are physically a lot smaller than what you might be used to seeing in a typical four-speed. The net result is a lot less rotating weight burdening your engine as you power out of the corner.
Of course, if you race Late Models or Modifieds on dirt, you probably already know this. Maybe what you don't know, however, is just how easy a Bert transmission is to rebuild. Yes, it is quite a bit different from just about everything else out there (a Brinn transmission is built on the same design principles), but its simplicity also makes it easy to maintain and rebuild.
Gear specialist Jim Cook, of Jim Cook Racing, says barring accident damage or severe abuse, a Bert transmission should last a complete season, or even two, between rebuilds. During a visit to his shop in Concord, North Carolina, Cook showed us how simple it is to inspect and rebuild a Bert using the company's rebuild kit. Because of time constraints, we tore down one customer's transmission and rebuilt a different unit that Cook had waiting for us. To improve efficiency and durability, Cook had the shafts and gears REM polished. He says this won't take a Fifth-Place car and send it to Victory Lane, but it will help reduce friction losses and keep oil temperatures down.
So, if you've got a Bert tranny that needs to be rebuilt, stop making excuses and get to work!
Don't Forget the Splines
Because the rear ends in dirt cars often see extreme articulation, many racers use Bert's ball-spline tailhousing. This innovation allows the tailhousing shaft to extend several inches without allowing dirt and sand to invade the housing when the shaft slides back into place. Cook recommends disassembling and cleaning the ball-spline shaft and housing after every two to four races.
