Current Transmission Designs

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Let's use the factory Eaton 18 speed as our example. 1st to 2nd shift is a 30% drop. Say you shift at 3,000 RPM. That's an 900 RPM drop. If the tires don't break loose, what's taking that drop? Something has to twist / snap. I've talked with guys who claim they can shift without letting up. I then watched them destroy their driveline. Be honest with yourself, it's your wallet. A simple burp of the throttle will save you a ton of head ache. 

There's a LOT of different techniques. Long story short, the harder the part, the easier it shatters. With all the questions on this one subject, I've started to look into it much further. As of 10/14/2025 we offer cryogenic freezing. The process takes 3 days once parts are ready. Typically parts go in on Friday and come out Monday morning. Interested, click here for more info.

This is changing. Machining has made multiple ratio options a real thing. Depending on how far your engine can drop between shifts will dictate the ratios used.

 Air compresses. The more room you give it, the longer it takes to compress. The way the race unit works, there's no need to range anyway. So why have extra stuff?

The first race transmission shifted just like any other transmission. After watching, it became obvious that everyone (racing loaded) was finishing in 5th gear (high side). That requires ranging, which takes time. Why not eliminate it and run a rear gear that doesn't stress the driveline? For those who are 3500RPM+,  welding a plate in the place of the low side synchronizer ring, running 3.70 or faster rear gear in order to avoid ranging, stop it. You're still taring stuff up, I've been watching. There's several trucks doing this. You're shaking your head at this, but still reading. May I suggest 3.90 - 4.33 rear gear with a 1.80 (top gear / low side) in the transmission?

In 2025 a few different designs were tried. 

*Every other tooth removed worked the best and failed the fastest. 2 events max was what I saw with those. If you're willing to rebuild your transmission after every event, then removing every other tooth is for you. Be sure to treat them or they may not last an event (weekend).

*Currently, shaving teeth has proven to be the most durable. Drivers are giving great feed back.

***Moving forward***

*2026 all clutch teeth will be shaved as this has proven durable and still shifts smooth.

*New clutches are under development. Stay tuned......

Custom units come with:

• Ratio options chosen by customer
• Billet inputshaft & billet mainshaft
• Shaved sliding clutches
• Aluminum rear bearing covers
• Complete oil system, inside and out
• Entire unit is cryogenically treated 
• Iron clutch (bell) housing.
• New yoke will be installed, of your choosing
• Reverse switch
• After dyno oil is drained, 50w AMSOIL is put in.
• You will re-use your pedal shafts. Too many different styles for me to keep track of.

After you get your transmission, there's on going service.

• Any questions you may have - phone call away.
• We will be at several events throughout the year. And will gladly help / answer questions. We have traveled to watch / help customers, when they go out for the first time. 
• At seasons end, get your transmission back for inspection. If needed, we can address any issues. Better to find them during winter, than mid-season.
• Ratio possibilities are increasing! Want to try something different? Can do that. We will go over options. And a timeline.