GM 4L80E are large in size, weight and in profits By now many torque converter rebuilders are learning the limits of rebuilding the enormous 4L80E torque converter.
Not only is this converter large in size, but its weight surpasses all but one domestic torque converter. Weighing in at sixty-seven pounds, this converter is all “iron.”
Therefore, rebuilding this converter requires special attention. Replacement of the impeller hub is always required, regardless of its appearance and condition.
Correct location during hub replacement will ensure an easier and more accurate balancing procedure.
In addition, careful attention and inspection of the lockup piston is vital. Air testing of the clutch plate is recommended to ensure cracks have not formed. Nearly fifty percent of the early designed pistons are found to be cracked due to poor design and material selection. New replacement pistons are available through Sonnax Industries and are highly recommended to be replaced every time to prevent a torque converter comeback.
Many friction material liners are available from a parts supplier in standard carbon, Kevlar. Be sure to match the correct liner with the proper ap plication.
Later designed 4L80E torque converters, 2001 and newer, do not fail as often, but inspection is still required. Cracks can show up even on the new designed units. This torque converter is available as a low stall, high stall and high stall dual – stator configuration. Never replace the original converter with anything other than the exact replacement.
For instance, if the vehicle has an original dual-stator design and is replaced with a single-stator design, the driveability characteristics become quite noticeable. A lack of performance and/or fuel economy may be affected.
Standard bearing and seal high and replacements are recommended as well as computer balancing. Careful alignment is critical as well as overall height. Rebuilding the 4 L80E torque converter can be quite profitable by following these simple guidelines to avoid returns and customer dissatisfaction.
Found in issue June 2005