Description

Mitsubishi Motors F3A21, F3A22, F4A21, F4A22, F4A23 1989 Service Manual

I’ve been wrenching for twenty-eight years – ASE Master, six bays in San Antonio. If you’re trying to rebuild one of these Mitsubishi automatic transmissions – the F3A21, F3A22, F4A21, F4A22, or F4A23 – without the factory manual, you’re going to waste time and likely damage parts. Aftermarket documentation is garbage for these units. They copy specs wrong, skip the valve body spring identification, and give you torque values that’ll strip threads. This 1989 Service Manual from Mitsubishi Motors is the only document you should trust.

Valve Body Spring Identification for 3-Speed and 4-Speed Models

Page 2 of this manual lays out the precautions: use a rubber mat, never reuse gaskets or oil seals, clean clutch discs with ATF only. That’s the kind of detail that keeps a transmission alive. The table of contents shows dedicated sections for the Valve Body (3-Speed Model) at 23A-14-1 and Valve Body (4-Speed Model) at 23A-15-1. Each subsection includes spring identification charts – exactly what you need when a check ball falls out and you’re staring at five springs that look identical.

What Torque Values Are Listed for This Transmission?

The Specifications chapter (23A-1-10) contains a full torque table. Pump housing bolts, valve body bolts, converter housing fasteners – all in foot-pounds. If you’ve ever snapped a bolt because a generic manual said “tighten to 20 ft-lbs” when the real spec is 14 ft-lbs, you understand why factory data matters. This manual also includes adjusting pressure plate, snap rings, and spacers – page 23A-1-6 – so you get the endplay right the first time.

19 Chapters Covering Every Component

From the Oil Pump (chapter 5) to the Kickdown Servo (chapter 16) to the Low-Reverse Brake (chapter 17), this manual walks you through disassembly, inspection, and reassembly. Each chapter lists the special tools required – chapter 2 covers that – and gives you the exact clearances and snap ring thicknesses. No guessing. No reprints.

Get the Right Oil Pump Clearances

The Oil Pump chapter includes gear backlash and side clearance specs. Measure with a feeler gauge or a dial indicator – your choice. But if you don’t have the factory numbers, you’ll either leave the pump too loose (loss of line pressure) or too tight (seizure). This manual tells you the acceptable range. Period.

Front Clutch and Rear Clutch: Factory Assembly Order

Chapters 6 and 7 detail the front and rear clutches. You get the exact number of steel and friction plates, the order of the return springs, and the clutch pack clearance specs. The same for the End Clutch (4-Speed Model) in chapter 8. If you mix up a wave spring or miss a snap ring, that transmission will have no forward or reverse. The manual doesn’t let you do that.

Who Needs This Manual?

DIY mechanics who bought a Mitsubishi from a salvage auction? Yes. Shop owners training a junior tech? Absolutely. Anyone who’s tried a Chilton’s for an automatic transmission rebuild knows the pain of missing data. This manual is for the guy who measures twice, checks the torque wrench calibration, and refuses to reuse a seal. If that’s you, stop relying on internet forum guesses.

Is this manual specific to these five models?

Yes. It covers F3A21, F3A22, F4A21, F4A22, and F4A23 transmissions from Mitsubishi. No other models.

Can I use this for a F4A21 valve body rebuild?

Absolutely. Chapter 15 is dedicated to the valve body for the 4-speed models (F4A21, F4A22, F4A23). It includes a valve body spring identification chart, check ball locations, and the order of disassembly. The manual also tells you which springs to measure with a micrometer and how to select the correct replacement. Do not attempt a valve body job without these pages – you will mix up pressure regulator and damper clutch springs and end up with a transmission that shifts like a truck over railroad tracks.

Does it include torque specs?

It has a dedicated torque specifications table in the Specifications chapter. That table covers all major fasteners for the transmission assembly.

Are wiring diagrams included?

No. This is a mechanical service manual for the transmission unit itself. Wiring for the control solenoid or TCM is not in this document.

Related Manuals: Mitsubishi Transmision Automatica F3A21 F4A23 Manual | Mitsubishi Motors LASER TALON 1990 Service Manual | Mitsubishi Motors R5M3, V5M3 2000 Service Manual – Factory Transmission Specs

External Info: See Automotive Industry Overview for general background on automatic transmission evolution. For comparison with manual gearboxes, check Manual Transmission.

Stop wasting time on pirated PDFs with watermarks and missing pages. This is the real deal – 146 pages, original Mitsubishi Motors publication. You want a transmission that shifts clean for 100,000 miles? Access the Factory Manual.