Preview of GM 2007 6L60E 6-speed trans New for its 2007 line, General Motors has released a new 6L80E 6-speed automatic transmission. This transmission is equipped with a 300mm torque converter, with many similarities to the current 4L60E converter. The similarities include the front cover, clutch piston assembly, woven carbon friction liner, impeller and stator. The differences include a newly designed impeller hub, turbine hub and inner stator race. Sonnax Industries has already prepared to supply replacement parts for these units. They should be available in the near future. The part number for this new converter is JMBX 2423-4544. This converter is built very well including a furnace brazed impeller, along with time tested and proven large diameter bearings, with larger diameter turbine splines similar to the 4L80E. It also weighs in at a hefty 45 lbs. dry.
Even though availability of new units may be limited , rebuilders can update the existing TMBX 300mm converter by simply replacing the turbine tub, inner sprag race and impeller hub; however, lack of these cores may also cause rebuilding issues.
The GM 6L80E is standard equipment in the 2007 Cadillac Escalade and is quite impressive to drive. This six speed transmission appears to be quite busy, along with converter engagements on and off quite often. Covered by a 100,000 mile warranty, rebuilders probably will not see many converters for rebuilding for a while. Transmission rebuild kits are not available yet, even from GM, but we thought we would share this sneak preview with you.