Overhauling or replacing a transmission is expensive. This is partly due to the cost of the assembly (in the case of a replacement) and partly because of the specialized training required to take it apart, clean it, and reassemble it.

Most auto repair shops will agree to install a replacement part, but will refuse to perform a complete overhaul. In fact, many shops that specialize in tranny repairs will strongly recommend a replacement. This is because of the enormous amount of time and effort involved with an overhaul. The problem is that a new model can cost ,000 or more. Even a remanufactured assembly can cost nearly as much.

Fortunately, many problems can be fixed without overhauling your transmission. In this article, I’ll describe the most common problems drivers experience and how they can be resolved. I’ll also explain the process mechanics go through when performing an overhaul.

Fluid Leaks

One of the first signs of a leak is a small pool of reddish fluid on the ground directly underneath your tranny. Depending upon the size of the leak and the amount of fluid loss, repairs may not be necessary if you’re willing to keep the levels topped off. You’ll need to check the levels consistently; a loss of fluid can quickly lead to expensive damage.

If the size of the leak is substantial, it’s a good idea to have a mechanic fix it as soon as possible. He’ll put your vehicle on a lift to examine the assembly from underneath. Once he identifies the leaks, he’ll reseal them. Most seals and gaskets can be resealed without the need to remove your car transmission. The exception is the front seal; if it forms a leak, there’s a high likelihood that your mechanic will need to remove the assembly to fix it. That can become expensive.

Odd Shifting Behavior

Under normal driving conditions, shifting should occur fluidly. However, when parts become worn, your transmission will begin to behave strangely. For example, hard shifting may occur where gear changes are accompanied by a jolt. Or, you might hear a high-pitched whine.

These are red flags – they indicate that there is something wrong. If your mechanic can address these issues early, he may be able to replace the responsible parts without taking the assembly out of your vehicle. If these problems are left unchecked, they will usually lead to bigger – and more costly – problems down the road. An overhaul or replacement may be necessary eventually.

What Happens During An Overhaul?

Your transmission is removed from your car and completely disassembled during an overhaul. Each piece is laid out, inspected, and cleaned. Parts that have become worn past the point of being useful are replaced. Most of the seals, bands, and gaskets are also replaced. Mechanics will typically discard your torque converter and install a remanufactured unit. Once everything has been inspected, cleaned, or replaced, the entire assembly is reassembled and placed back into your car. An overhaul is normally a long, costly, and labor-intensive process.

The takeaway is this: be aware of fluid leaks and odd behavior. If you notice them, have a mechanic take a look as soon as possible. You’ll reduce further damance and therefore reduce the chances you’ll need a overhauled, remanufactured, or new transmission.