Automatic & Manual Transmission Replacement Parts

To Rebuild Or Not Rebuild Your Transmission

When it comes to auto repairs, it's important to be up to speed on warnings signs that a system needs maintenance or even an overhaul. Start by evaluating your car or truck's performance to determine if your vehicle needs a transmission flush and fluid change, or if you need to rebuild the transmission and replace key components.

Has your gas milage decreased? Is the shifting choppy or is the engine stalling? Are you noticing grinding or shaking? Is there smoke coming from under the hood? Is a warning light appearing on your dashboard? The causes for these potential transmission issues can range from a bad clutch to worn gears, or simply damaged sensors. Whether you drive a Honda Odyssey, Nissan Pathfinder or a Hyundai Sonata, NAPA AUTO PARTS always goes the extra mile to deliver quality automotive parts.

An oil puddle under your vehicle is another warning sign. Various fluids keep a transmission lubricated, clean, cool and sealed. The oil pan gasket is the primary gasket that keeps oil from leaking out of your engine. The valve cover gasket goes over the engine cylinder head, preventing oil or fuel from leaking around the camshafts, rockers and valves. Over time, gaskets can break down or shrink, and parts like transmission mounts, master cylinders, slave cylinders, flex plates and drive friction discs can wear out.

Get Up To Speed On A Standard Transmission

A transmission converts the engine's output to rotate the axles and the drive wheels. For manual transmissions, the clutch, flywheel and pressure plate handle power transmission. For automatic transmissions, which select an appropriate gear ratio without any operator intervention, the torque converter transmits the power flow from the engine. The valve body shifts the gears using fluid pressures in response to engine RPM, speed and throttle input.

The most common type of automatic transmission utilizes hydraulic power to shift, using a fluid coupling converter and gearsets. Accumulators usually are installed in hydraulic systems to store energy and to smooth out pulsations. In a typical 5-speed transmission, the drive unit-or gearbox-allows for the adjustment of gears as the vehicle's speed changes. A continuously variable transmission (CVT) operates both an input shaft and output shaft with different rotational speeds that can be varied continuously.

Another key factor in a vehicle's transmission is the number of cylinders. The more chambers-or cylinders-a vehicle engine contains, the more power in the form of torque it produces. The intake manifold gasket seals the intake manifold against the cylinder head, keeping the fuel and air mixture airtight. In some cases, it also separates the fuel and air channels from the coolant channels. Other critical pieces of a car's transmission system to check for potential replacement or restoration include the transfer case, transmission mount, fluid pump, push rod, shift solenoid, bearing carrier assembly and power take-off control valve console.

It's Clutch Time

The mechanics of a clutch briefly disconnect or separate the engine from the transmission system, allowing the driver to smoothly change gears. The clutch is usually mounted directly to the face of the engine's flywheel, and both are enclosed in the bellhousing. Friction clutches, the most common in automatics, creates friction between the flywheel on the engine and the clutch plate on the transmission, and that force rotates the wheels to move the car.

Older automobiles often utilize centrifugal clutches, which automatically engage or disengage as the speed of the input shaft increases or decreases. The torque converter clutch was designed to improve the fuel efficiency of automatic transmissions. The use of torque converters, which lock up beyond a certain speed or in higher gear ratios, eliminates power loss.

Instead of relying on mechanical or hydraulic control over a transmission system, newer vehicles use a transmission control module-a computer that assists the automatic transmission in choosing the best gear to be in at any given time. Ensuring the driving performance and fuel economy are at an optimal level.

Before beginning any DIY work on your vehicle's clutch, consider investing in tools like the clutch adjuster and gear adjuster. And reference this list of transmissions parts that are vital in the clean and smooth operation of your car or truck's system:

• Shaft key
• Shim
• Release lever
• Ball stud
• Bleeder screw
• Thrust washer
• Transmission cooling lines
• Transmission cables and extensions
• Transmission shift cable bracket
• Transmission shift indicator, cover plate and lock
• Shifter cable
• Shifter arm, knob and handle
• Shifter spool assembly
• Shift tube pin and shift tube clamp
• Pedal, pedal bracket and pedal pad

Participating NAPA AUTO PARTS stores now offer a Buy Online-Pick Up in Store option to better serve you. Add the parts you need to your online shopping cart, pay online to check out, and the store will send you an email when the order is ready.