4L60E and 4L65E transmission suffers from holiday travel blues
Now that we have reached peek
travel time for the summer season, a little special care may help protect your customers’ transmissions.
The 4L60/65E transmission, which is found in many General Motors’ pickups and SUVs, are hitting the road towing boats, trailers, campers, etc., at near and sometimes over the manufacturers gross vehicle weight. This puts on additional stress and heat to the transmission which can quickly lead to torque converter failure. The late model 1997-2004 transmission equipped with PWM and/or CCC cubed systems can operate at temperatures over 220 degrees. It is common that torque converter failure can start around 240 degrees.
Because of the extra stress and demand placed on the transmission and converter, many times warranty claims become an increasing issue. Many times failure is not direct result of the converter itself but rather the way the customer overloads the vehicle. You can help reduce your warranty claims if your customers are ordering torque converters for these vehicles by offering them a heavy duty converter designed to reduce heat. This can be done by installing larger roller bearings and keeping converter efficiency up by reducing clearances to minimal standards.
Offering a slightly lower stall speed converter for towing purposes will also help reduce heat. This can be achieved by both reducing the primary pump fin angles and by machining .050 to .075 across the impeller side of the stator.
According to a local Chevron oil distributor, the types of transmission fluids available is staggering. You must be very careful and advise your customers about the potential danger of using a generic and/or “no labelled” types of ATF lubricant.
If there is no API (American Petroleum Institute) number located on the label, it is beneficial to pass up the product regardless of the price saving qualities it may bring your company. Many types of ATF cannot survive the extra stress and torment of the travel season. It is also recommended to add a transmission cooler to the vehicle to protect the transmission and converter while protecting the rebuilder from legitimate warranty claim.
Found in issue 07, 2004