The Raybestos Powertrain ZPAK™ Specializes in Longevity and Towing Applications

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February 27, 2019

Raybestos Powertrain is known for its unique product design and manufacturing process that allows us to develop and patent products such as the ZPak®. ZPak single-sided clutch systems are a complete Raybestos Powertrain re-design that reduces hot spotting and increases heat sink to outperform OE heat capacity by more than 30 percent in certain applications. While many people believe that we designed the ZPak specifically for racing applications, it was originally designed for enhancing performance and longevity in towing applications.

ZPak technology was developed in the early 2000s and the 4L60E 3-4 Clutch ZPak was the first one released by Raybestos Powertrain. This 4L60E transmission was prone to having several issues in the 90s, particularly with the primary focus on improving upon the OE design in order to fix hot spotting and coning of the steel plates on the 4L60E transmission 3-4 clutch. Raybestos Powertrain took advantage of this issue and found the solution with the ZPak, a product capable of taking the heat without coning. Our ability to utilize our technical center, specifically using dyno testing, was a key factor in the material design of the ZPak. The single sided clutch design’s ability to change the loading factor on the clutch was a breakthrough in our development of the ZPak. The GPZ material that we used allowed us to improve the single sided clutch design in a clutch pack that normally is not capable of taking that much abuse.

To recap, the ZPak was created to improve upon OE clutch pack designs in order to enhance performance and longevity in towing and some high stress racing applications. While the ZPak was not designed specifically for racing applications, it could work in certain racing applications depending upon the conditions and setup of the transmission. Raybestos Powertrain Sales and Product Development Support Engineer, Irvin Gers, says “the ZPak was designed for the working man.” Raybestos Powertrain manufactures specific products that meet the requirements for racing applications with Stage-1 friction clutch plates for vehicles that you drive on the street, but also race (street/strip applications). Gen2 blue plates are meant for serious racing applications that you tow to the drag strip or track. ZPaks are currently available for:

4L60E 3-4 Clutch | RZP-001
6L80/6L90 3-5 Reverse | RZP-005
68RFE Overdrive | RZP-008

To find a distributor near you, visit


posted by: Nathan Truncone   comments: 0

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