Description

ATSG 350C Service Manual – Factory Rebuild Specs for the 350 Transmission

You’re looking at the ATSG 350C Service Manual. Before you crack open that 350 transmission, know that this booklet is 75 pages of factory-level instruction. It’s not a pamphlet. It’s the same material the Automatic Transmission Service Group (ATSG) puts out for shops that bill by the job. If you skip the pressure checks in Section 7A, you’ll be pulling the trans a second time. I’ve seen it happen. This manual covers the 350C from general description straight through to final reassembly – no third-party shortcuts, no generic values.

350C Transmission: Full Tear-Down Sequence

The manual walks you through a logical order: extension housing removal, speedometer drive gear, oil outlet shaft, then the valve body and pump. Page 2 gives you the pressure table (Fig. 350C-2) – line pressure at various throttle openings. That table is worth the price alone if you’ve ever chased a slipping band. Every section under “Reparacion de Unidades” lists disassembly, inspection, and reassembly for each subassembly. The oil pump alone gets four pages of step-by-step. Use the fluid level check procedure in Section 7A before you do anything else – a low level will mimic a bad clutch.

Does This Manual Cover the Valve Body and Governor?

Yes, and it gives them separate chapters. The main valve body (“Caja de válvulas”) includes lubrication, inspection, and reassembly. Then there’s a separate “Cuerpo de válvulas auxiliares” (auxiliary valve body) with its own disassembly and rearmado. The governor assembly (“Conjunto regulador”) is covered under Sección 250C – includes the regulator and driven gear housing. If your 350C shifts erratic, start with the governor: remove, inspect for stuck weights, clean the valve. This manual tells you exactly how to reassemble without mixing up check balls.

5 Clutch and Servo Disassembly Procedures

Four clutch packs and one servo assembly each get their own section: direct clutch, forward clutch, propulsor clutch (this is the forward drum, actually), reverse/low clutch, and the servo. Each section shows the order of plate removal, what to measure for clutch pack clearance, and what to look for during inspection. The manual uses Imperial measurements – feeler gauge specs are in thousandths of an inch. The rearmado (reassembly) steps tell you which spring retainer goes where. I’ve rebuilt a 350C using this exact manual and it came out right the first time because I followed the clutch end-play checks.

Get the Factory Pressure Specs

Aftermarket data sheets often skip the line pressure check. Page 2 of this manual has a table of operating pressures at idle and stall for each gear range. You’ll need a pressure gauge that reads to 200 psi. The manual also covers the pressure regulator verification – vacuum modulator adjustment, throttle valve cable. If you don’t have spec pressure, you’re chasing a ghost. The ATSG manual gives you the numbers. Use them.

Diagnosis: Following the Factory Diagnosis Order

The diagnosis chapter starts with a clear order: fluid level and mount check, then line pressure, manual linkage, pressure regulators, then the actual diagnostic table. That table lists conditions like “No drive in forward” and gives probable causes and corrections. It’s not a generic list – it’s specific to the 350C valve body and governor setup. Cross-reference with the pressure table on page 2. If you see low reverse pressure, the manual points you to the direct clutch or servo. Skip this step and you’ll be pulling the pan twice.

Torque Values and Where They Show Up

Every assembly section includes torque specs for the fasteners – pump bolts, valve body screws, clutch retaining bolts. You won’t find a separate torque chart; instead, the values are given in the reassembly text. Use a beam-type torque wrench for the valve body – 8–12 ft-lb range. The pump bolts call for 18–22 ft-lb. The manual doesn’t clutter the page with numbers everywhere; it keeps them where they belong: right next to the step. That’s how a shop manual should be written.

Why This Manual Beats Aftermarket Copies

This is an original ATSG publication, not a recompiled PDF from someone’s scanned napkin. The ATSG 350C Service Manual was written by technicians for technicians – Robert D. Cherrnay and C.W. Smith are listed as technical director and repair advisor. The document includes their names, their shop group, and a Miami address. That’s accountability. Aftermarket reprints often lose the pressure table clarity or crop the edge of the diagnostic chart. This one is clean, 75 pages, with every bookmark intact. If you need a manual for a different trans, check the ATSG C-5 Service Manual – Factory Torque Specs & Rebuild Guide or the ATSG L3N71B Technical Manual | Factory Specs for Nissan Automatic Transmission. For three-speed Chrysler variants, the ATSG JR403-E Technical Manual – Factory Specs for Electromatic Transmission covers similar pump and valve body logic.

Is this manual in English?

No, it’s in Spanish.

What does the diagnosis section cover?

The diagnosis chapter (starting on page 1 under DIAGNOSIS) walks you through a systematic check: first the fluid level and mount, then line pressure check (Section 7A), manual linkage adjustment, pressure regulator verification, and then a full diagnostic table of common problems. For example, ‘No marcha engranada’ (no drive) lists probable causes and corrections. This eliminates the guesswork that wastes time on a hoist. It’s specific to the 350C’s hydraulic circuits, not a generic list.

For background on why factory documentation matters, see the Automotive Industry Overview. Cross-referencing with other OEM data, like the Automotive Industry Overview, can validate specs. But for your 350C, nothing beats the original ATSG book. Access the Factory Manual and put it on your bench before you pull that first pan bolt.