Automatic Transmission

The modern automatic transmission is by far, the most complicated mechanical component in today’s automobile. Automatic transmissions contain mechanical systems, hydraulic systems, electrical systems and computer controls, all working together in perfect harmony which goes virtually unnoticed until there is a problem.

Automatic transmissions have become more reliable in recent years, but still it’s a most-easy-to-break and very-expensive-to-fix part of the vehicle. Today’s automatic transmissions consist of hundreds of individual components. During a major repair, each one is removed, cleaned, and inspected to exacting tolerances. Any worn or damaged parts are repaired or replaced.

Then each part is put together into one of many subassemblies. Each subassembly must be adjusted, and tested for proper operation. Then the subassemblies must be assembled into the transmission case, where the adjustment and testing procedure begins all over again.

Finally, once the transmission is completely assembled, it has to be reinstalled.

Types of Transmission Repairs

Adjustments and In-Car Repairs

There are several problems that can be resolved with an adjustment (A simple adjustment is one that can be made without removing the transmission from the vehicle.) or minor repair.

If a late model transmission (computer-controlled transmissions started becoming popular in the early ’90s) is not shifting properly, it is often the result of a computer sending incorrect signals due to a faulty sensor, or the transmission is not reacting to the computer command because of a bad connection or defective solenoid pack.

Reseal job

A transmission is resealed in order to repair external transmission fluid leaks. If you see spots of red oil on the ground under the car, your transmission may be a candidate for a reseal job. In order to check a transmission for leaks, a technician will put the car on a lift and examine the unit for signs of oil leaks. If a leak is spotted at any of the external seals or gaskets and the transmission otherwise performs well, we will most likely recommend that the transmission be resealed.

Many of the external seals can be replaced while the transmission is still in the car but, if the front seal must be replaced, the transmission must first be removed from the vehicle in order to gain access to it, making it a much costlier job.

Replace accessible parts

There are a number of parts that are accessible without requiring the removal of the complete transmission. Many of the control parts including most of the electrical parts are serviceable by simply removing the oil pan. The parts that are accessible, however, vary from transmission to transmission and we hesitate to provide a warranty on external repairs for the simple reason that they cannot see if there are any additional internal problems in the components that are only accessible by transmission removal.

Complete Overhaul (Rebuild)

In a complete overhaul (also known as rebuilding a transmission), the transmission is removed from the vehicle and completely disassembled with the parts laid out on a workbench. Each part is inspected for wear and damage and then either cleaned in a special cleaning solution, or replaced with another part depending on its condition. Parts that have friction surfaces, such as bands and clutches are replaced as are all seals and gaskets. The torque converter is also replaced, usually with a remanufactured one. Technical service bulletins are checked to see if the auto manufacturer recommends any modifications to correct design defects that were discovered after the transmission was built. Automobile manufacturers often make upgrade kits available to transmission shops to resolve these design defects.

Remanufactured Unit vs. Rebuilt (Overhaul) Unit

When a transmission requires an overhaul, there are generally two options that you may have. The first is to remove your existing transmission and overhaul it, then put the same, newly rebuilt unit back in your car. The second option is to replace your existing unit with another unit that has already been or remanufactured. Below is a comparison of Rebuilt vs. Remanufactured:

Rebuilt Unit

To rebuild is to recondition by cleaning, inspecting and replacing severely worn or broken parts. Serviceable parts are reused within the manufacturer’s acceptable wear limits.

Remanufactured

To remanufacture is to make as close to new as possible. Wearable parts are automatically replaced. All core material is closely inspected and checked against original equipment specifications for correct dimensional tolerances.

Replacement parts are new and made in the same production process as original equipment. Testing is performed to manufacturer specifications and original production standards.