4L60 transmission is produced by General Motors. It was first introduced in the public in 1991 and it was later upgraded to electronic (computer controlled) 4L60e version. Today 4L60e is one of the most popular rear wheel drive transmissions and it can be found in different vehicles including lighter-duty pickup trucks and cars. One of the best things about this type of transmission is the fact that it can be rebuilt really easy. Of course, before anyone starts with the procedure they should know the basic steps.
First of all, you need to disassemble the unit in the right way. You need to find suitable tools (screwdrivers) to remove the output speed sensor, rear seal from the extension housing, extension housing, servo cover snap ring and the rest of the servo components. After that you will need to remove the filter and disconnect the electrical wiring. There are more than 30 parts which need to be disassembled, cleaned, repaired or replaced. This process lasts long and those who are planning to do it should be very careful in order to avoid damaging the parts which are in good condition.
The second step in rebuilding the 4L60E transmission is the pump assembly. In this way you will have the chance to correct the torque and solve its drainback problem. Excessive clearance in some (there are three pump areas) areas is usually the cause of this problem. The first area is the pump rotor and pump slide to top of pump pocket clearance. Make this clearance less than 0.003’’. Torque convertor hub to pump bushing clearance is another pump area that needs to be checked. Finally, stator support bushing that leads to the turbine shaft journal clearance.
The next step is to disassemble and then assemble the input drum. This is also a complicated process, but if you follow the instructions you can finish it quickly. The disassembling usually doesn’t last for a long period of time while the assembling will take more time.
The reverse drum needs to be checked and cleaned. In some cases you will have to resurface some parts of the reverse drum. Make sure you are using adequate tools for this procedure.
Gear train is the area that covers the main internal metal elements not covered in another section of this program. These elements usually include – roller clutches, gear assemblies, sprags and shafts. You will have to disassemble, clean and assemble the unit.
Case needs to be prepared in the right way for reassembling. Check for any damages on the case lugs and bolt holes. After that, you will have to assemble the 4L60e valve body. According to experienced auto repairers this task is relatively easy. The retainer clips are not difficult to work with and the valves used in this transmission system are made of steel which makes the job even easier.
Finally, once you are done with this, you will have to assemble the unit.
Although rebuilding a 4L60e transmission doesn’t look difficult, the best idea is to leave this work to real professionals who have experience in this field.