Stay-at-Home Projects: Upgrading Your TH400

Stay-at-Home Projects: Upgrading Your TH400

Being at home can get old when you don’t have a project to work on. So, here’s something to keep you occupied, keep your hands busy and keep your car in racing condition. 

When building a high performance 3-speed transmission, the direct drum is one of the most important components to upgrade as it impacts reliability, safety, and performance of your transmission. As in the case of our TH400, the shafts and gear sets are very durable, and, if the drum is upgraded, the power rating of the transmission nearly doubles.

BTE offers three solutions for the direct drum replacement in a TH400 transmission:

34 Element Sprag Upgrade
In our experience, the original spring and roller isn't reliable above 500 ft-lbs in most scenarios. A modified original factory drum with this sprag is suitable for most cars making up to 750 ft-lbs of torque.

36 Element Sprag Upgrade
Heavier car? We offer an even stronger 36 element sprag on the factory drum. This modified drum has a much larger inner and outer race design, so as many as five intermediate racing clutches can be installed (and are included with the drum). We also include a billet pressure plate.

TH400 Aluminum Direct Drum with Pro Mod Sprag
Our best TH400 direct drum is a hybrid aluminum and steel design. It still has the 36 element sprag and the five clutch intermediate pack, but the clutch drum portion is constructed from 7075-T6 hard anodized aluminum. This lightweight and durable material reduces the weight by 50% compared to the original factory drum. Why does that matter? Weight reduction improves the safety of the drum, the life of the sprag, and the performance of the car—an all-around win.

BTE's aluminum direct drum is superior to other designs because of its steel center. The splines are less prone to damage than the full aluminum drums, and the steel reduces wear from sealing rings (another problem with full aluminum drums). When utilizing a "clean neutral" valve body, an aluminum direct drum must be used.

We’re proud to be Part of Your Racing Team and are here to help with any rebuild projects and offer any parts recommendations you may need. Get in touch at 1-800-626-1828 or visit our website to place an order.

Posted by Amber Ambrose at 2:14 PM