More horses for your chariot.

Welcome to Circle D’s Performance page. We specialize in Ford, GM and Dodge rear-wheel drive performance transmissions. We pride ourselves in staying in the forefront of our industry, technology, research & development and our commitment to you, the customer. With our full machine shop capabilities, ASE certified technicians and over 38 years of experience, we can get your horsepower to the pavement where it belongs. From custom show vehicles, street & strip, mild to wild, we can build and custom tune your transmission. We also specialize in extreme duty diesel transmissions — from towing giant loads to blazing the drag strip.

Heavy-Duty, Custom Performance Modifications are available for the Following Units:

GM: 200R4, 700R4, 400, 350, 4L60/65/70E, 4L80E Allison LCT1000, 6L80/90

Ford: C4, C6, AOD, 4R70W, 5R55S/W, 4R100, Torque Shift 5R110W, 6R60, 6R80 & Torque Shift 6R140

Dodge: 904, 727, 46/47/48 RE, 545RFE & 68RFE

Circle D custom rebuilds these units, please contact us for a quote for your application.