Description

Mitsubishi R4M21, R5M21, V5M21 1998 Service Manual

You’ve got a transmission on the bench that’s grinding or popping out of gear. You pull up a forum post, find a generic torque chart, and end up snapping a bolt because the spec was for a different model. I’ve seen it. That’s why when you grab the Mitsubishi R4M21, R5M21, V5M21 1998 Service Manual, you’re holding the exact document Mitsubishi’s techs used. 250 pages of factory data, no aftermarket shortcuts. Let’s get into what’s between the covers.

Torque Specs and Service Specifications

Page 22A-1-12 lists every torque value for the transmission assembly. Need the load on the mainshaft nut? It’s there. The manual doesn’t give you a range and tell you to “tighten to spec” — it gives you a number and a sequence. You’ll find service specifications on page 22A-1-11 that cover gear backlash, preload, and end play. If you’re rebuilding an R5M21 or setting up a V5M21 transfer case, those numbers are what keep the bearings alive.

What the 250 Pages Cover

This isn’t a highlights reel. The table of contents runs from GENERAL INFORMATION through to TRANSFER CASE PLATE. You get separate chapters for Control Housing, Controller, Countershaft, Extension Housing, MainDrive Gear, Mainshaft, Speedometer Gear, and the full transfer breakdown (including the V5M21-A variant). The manual also includes a section on special tools (page 22A-2-1) so you know exactly what puller or press adaptor you’ll need before you start.

Transfer Case Coverage: V5M21-A vs Other Models

If you’re working on a V5M21-A, the manual splits the transfer section into two: chapter 11 for non-A units and chapter 11a specifically for the V5M21-A. Same deal for the rear output shaft and input shaft. That level of separation means you don’t have to guess which snap ring thickness or spacer applies to your build. The sealants and grease list on page 22A-1-14 tells you exactly what to put on the mating surfaces — no “use RTV” nonsense.

3 Sections for a Transmission Rebuild

For a full teardown, you’ll live in chapters 3 through 9. The TRANSMISSION chapter (22A-3-1) covers the general disassembly. Then the CONTROL HOUSING (22A-4-1) and CONTROLLER (22A-5-1) get into the shift mechanisms. The COUNTERSHAFT (22A-6-1) and MAINSHAFT (22A-9-1) chapters walk you through bearing removal and gear stack clearance. The manual includes ADJUSTMENT SNAP RINGS AND SPACERS on page 22A-1-15 — that’s where you find the shim selection process. Skip that step and you’ll get a transmission that howls.

Source Authenticity: OEM Factory Documentation

Compare this to a aftermarket CD that reprints someone else’s notes. Mitsubishi Motors Corporation printed this in December 1998 (revision PWEE8914-G). The wiring diagrams, torque specs, and assembly sequences are the same ones that went to the dealerships. When the Manual Transmission section says “flanged bearings have been employed,” that’s a production change you need to know about — aftermarket manuals usually miss that. If you want to cross-reference with a related platform, check the Mitsubishi Dodge Stealth R/T Turbo 3000GT VR4 GTO Service Manual for transfer case similarities. Or for a different engine family, the Mitsubishi Eclipse Spyder 1996 Service Manual – Factory Specs & Wiring covers the 420A and 4G63 driveline. And if you’re working on diesel applications, the Mitsubishi SS-SERIES 2007 Service Manual – Factory Diesel Specs is useful.

Need an overview of the industry? The Automotive Industry Overview gives context, but this manual is where the actual work happens.

FAQ

Does this manual include the V5M21 transfer case?

Yes. Separate chapters for V5M21-A and non-A variants.

What if I’m missing a snap ring thickness spec for the mainshaft?

The manual lists adjustment snap rings and spacers on page 22A-1-15 with part numbers and thickness ranges. You’ll find the clearance measurement procedure in the MAINSHAFT chapter. Without that spec, you’re guessing on bearing preload — and guessing leads to noise and early failure. The factory data gives you the exact method using a dial indicator and a press, with the acceptable range in thousandths of an inch. Don’t rely on internet forums for those numbers; use the document that Mitsubishi built the transmission around.

You’ve got a transmission to put back together. Don’t reach for a third-party summary. Access the Factory Manual and work from the same page the engineers signed off on.