New GM25HDX torque converter now available!
The GM25HDX torque converter is our latest addition to our heavy duty torque converter product line. This new model is based on the proven and popular GM25 torque converter, but offers several key upgrades to enhance strength and durability in extreme high output applications.

Upgrades include the following:
• One-piece heat treated billet steel pump hub and flange which provides maximum anti-ballooning properties.
• Full silicon spot brazing of every impeller and turbine fin to reinforce the fins and prevent fin failure from metal fatigue.
• Full roller bearing construction including Torrington needle roller bearings between the turbine and cover,
between the turbine and stator, and between the stator and impeller.
• Heat treated billet steel turbine spline.
• Custom heavy duty fully welded mounting ring with large GM bolt pattern, fits 168 tooth flexplate
(recommend torque converter bolt and nut kit part number HP7454).
• Extreme duty 10-strut mechanical diode.
The GM25HDX is a 12" torque converter, and features an advertised stall speed rating of 2,500 RPM, although this converter like any other torque converter will provide a range of stall speed based on the load that it is subjected to. All of the heavy duty upgrades make this converter compatible for use with transbrakes as well as with all power adders including nitrous oxide, superchargers, and turbochargers. This converter is an ideal choice for a huge variety of applications, including street and street/strip vehicles, off-road vehicles, sand/mud racing, and pulling competition. This converter is designed for use with TH400 transmissions, non-lock-up TH350 transmissions, and Powerglide transmissions that utilize a turbo-style 30-spline input shaft and that have sufficient bellhousing clearance for a 12" torque converter. We recommend torque converter bolt and nut kit part number HP7454 for use with the GM25HDX torque converter. If you have a high torque combination that requires lower stall speed while offering unbeatable strength, efficiency, and performance, then the GM25HDX is the right choice for you.
