Automatic Transmission Components

What Are The Main Automatic Transmission Components?

The main automatic transmission components are the torque converter, oil pump, valve body, planetary gear sets, and the clutches and bands they control. All of them have to work together for your automatic transmissions to shift on time and hold power.

Power starts at the flexplate, which connects the engine to the torque converter. If you're replacing either one, shop flexplate and flywheel covers and torque converters. Read our guide on how to choose a torque converter before you settle on a stall speed.

Inside the case, the oil pump pressurizes fluid and the valve body directs it to the clutch packs and bands. That sequence decides which planetary gear set is working and when the next shift happens. Worn seals, a sticking valve, or a misadjusted kickdown cable can throw that timing off, so replace supporting parts while the unit is apart.

Automatic Transmission Gearbox Parts For Rebuilds And Swaps

Automatic transmission gearbox parts for rebuilds and swaps start with the case, the adapter hardware, and sometimes a complete unit. TCI covers several of these, including a Superglide 1-piece case with liner for Powerglide-style builds. TCI also offers a Heavy-Duty RV Ford C6 transmission for 1966-91 applications.

If you're mixing makes, the TCI adapter plate kit mates a Ford 289, 302, 351C, or 351W engine to a GM transmission. That opens up more transmission choices without changing your engine. For GM-powered projects, our guide to automatic transmissions for LS engine swaps walks through common pairings.

Any time the pan comes off, plan on fresh seals and a clean filter. Order automatic transmission filters and gaskets with your hard parts. That way you aren't waiting on a second shipment before the transmission goes back in the car.

Valve Bodies, Lockup Kits, And Shift Control Parts

Valve bodies, lockup kits, and shift control parts decide when and how firmly your automatic shifts. A full-manual valve body removes automatic upshifts, so you select each gear yourself. Racers run them because every shift happens exactly when the driver calls it. Speedmaster offers a billet-aluminum full-manual valve body for the GM TH400.

Here's what you'll find for shift control in this category:

• Full-manual valve bodies for TH400 race builds
• Trans Go lockup kits for the TH200-4R
• Lokar Vintage Series kickdown cable kits

For street cars that need firmer shifts without going full manual, look at automatic transmission shift improvement kits. Kickdown cable adjustment matters too. The cable tells the transmission when to downshift under throttle. A stretched or kinked cable can leave you a gear short when you need it.

Tailshaft Housings, Seals, And Speedometer Gears

Tailshaft housings, seals, and speedometer gears handle the back of the transmission, where it meets the driveshaft and drives your speedometer. Speedmaster makes an aluminum transmission tailshaft housing for the Ford C4. You'll also find an aluminum tailhousing for the GM TH400.

Seals keep fluid inside where shafts pass through the case. ACDelco input shaft seals and prop shaft slip yoke seals are straightforward replacements that stop leaks before they reach your garage floor. Speedometer drive gears for the Turbo 350 and 1967-1969 Powerglide help your speedometer read correctly after a tire or rear gear change.

This category also carries supporting parts for specific vehicles. Look for transmission lines for Chevy and GMC pickups and 1970-1972 Pontiac Grand Prix models. There's also a pressure sensor for 2000-2004 Dodge and Jeep models, a parking pawl, and a Lokar braided stainless-steel transmission dipstick for the GM TH-350.

How To Choose Automatic Transmission Parts For Your Vehicle

To choose automatic transmission parts, start with your exact transmission model, then confirm vehicle fitment. Use Add a Vehicle to narrow 5,828 items to parts listed for your year, make, and model. Many parts fit by transmission rather than vehicle, so know whether you're running a TH350, TH400, C4, C6, or another unit.

Next, filter by Part Type, Brand, Product Line, or Material. Material matters most on tailhousings and valve bodies, where racers often choose aluminum or billet aluminum. Restorers can find small hardware too, like shifter plate screws for 1964-1970 Mustangs. Check the product details on each listing before you order.

Planning a full rebuild? Our 4L60E transmission rebuild buying guide covers what to replace while the unit is apart. Once you know your transmission, part type, and fitment, shop automatic transmission components now and get back to building.