Products Sonnax introduces Low/Reverse servo pistons for GM TH400, 4L80-E Advertisement ByAlex Crissey on March 24, 2022 Sonnax has introduced new Low/Reverse servo pistons for GM applications. According to the company, the new pistons are built for GM TH400 and 4L80-E transmissions, and are made of high-strength, billet aluminum to prevent failure.Click Here to Read MoreAdvertisement Advertisement In this article:GM, GM 4L80-E, GM TH400, Sonnax Products: RatioTek introduces new transmission tuner kits for Ford, BMW, ZF Products: Raybestos introduces Ford 10R80 clutch pack Products: Sonnax highlights oversized overdrive servo regulator valve kit Products: Alto introduces overdrive piston retainer for Chrysler transmissions Advertisement WEBINARS Watch a webinar for free on-demand! E-MAGAZINE Read the most recent edition of Transmission Digest. SUBSCRIBE Stay up to date by signing up for Transmission Digest newsletters.