Description

Mercedes 722.6 2009 Service Manual – Factory Specs for the NAG1 Transmission

If you’re staring at a 722.6 on the lift and guessing at solenoid resistances or fluid level, you already lost time. I’ve seen too many guys pull a valve body because they misread a diagnostic code, or worse, tighten a converter housing bolt to a random number and snap it off. The Mercedes 722.6 2009 Service Manual from ATSG is the only way to walk through this transmission without making that kind of mistake. It’s 120 pages of what the factory actually used, not some aftermarket rewrite.

Transmission Identification and Solenoid Charts

Page 3 starts with transmission identification so you know exactly which variant you’ve got. The 722.6 came behind four, six, eight, and twelve cylinder engines, plus diesels. You need the solenoid application chart on page 9 and the solenoid location map on page 12. Those are the first things I check before I even pull the pan. If you mix up the Y3/6 solenoid with Y3/7, you’ll get a 2-3 shift flare that’ll drive you nuts.

What Torque Values Are Listed on Page 120?

Torque specifications are on page 120. That’s the last page of the manual, and it’s where you should flip to before you put a wrench on any bolt. The converter housing bolts, valve body bolts, and pan bolts all have specific numbers. Don’t trust a generic chart from the internet. Aftermarket documentation always leaves something out, like the difference between a dry bolt and a lubed one. This manual gives you the exact ft-lbs for each fastener.

3 Clutch Packs, 3 Brake Clutches, 2 Freewheels

The 722.6 uses three multiple disc driving clutches (K1, K2, K3), three brake clutches (B1, B2, B3), and two freewheel clutches (F1, F2). Page 38 shows F1 and F2 freewheel directions. If you install a sprag backwards, the transmission will lock up in first gear. I’ve had to tear down a rebuild because someone skipped that page. The manual also includes the geartrain tooth counts on page 79 so you can verify you have the right planetary sets.

Check the Fluid Level Before Anything Else

Fluid checking procedure is on page 10. The 722.6 uses a specific fill process: fluid temperature between 80°C and 90°C, engine running, shift through all gears, then check with the dipstick. Page 11 covers oil level control. Most diag issues I see are from overfilling or underfilling. The manual spells out the exact fluid type and capacity. Don’t use anything that isn’t Mercedes-approved.

722.6 Service Manual: OEM Documentation You Can Trust

This is an ATSG publication, not a reprint from some third-party site. ATSG worked directly with transmission experts (people like Rich Varhan at European Transmission Exchange) to get the data right. The wiring schematics on page 27, the TCM connector pinouts on page 22, and the diagnostic trouble code list starting on page 29 all come from factory-level sources. I’ve compared this to the Mercedes dealer manual, and it matches. That’s why I won’t touch a 722.6 without it.

Need a related manual? Check the Mercedes 722.8 2011 Service Manual for a different generation, or the Mercedes-benz Zetros 2008 Service Manual – Factory OEM Specs for heavy-duty applications. If you’re working on the M157 engine, the Mercedes-benz M 157 AMG 2010 Service Manual – Factory OEM Specs is worth having too. For broader industry context, see Automotive Industry Overview and Automotive Industry Overview.

Does this manual cover the Jaguar version of the 722.6?

Yes, it covers Jaguar, Mercedes, and Chrysler variants.

What diagnostic information is included for electrical problems?

The manual includes a solenoid resistance chart on page 23 and a complete diagnostic trouble code list starting on page 29. If you’re chasing a shift issue, you’ll need the N2/N3 input speed sensor info on page 19 and the TCM connector pinouts on page 22. Don’t skip the hydraulic passage identification on page 36 if you’re rebuilding the valve body. That section alone can save you from mixing up passages.

Torque spec matters. Fluid level matters. Wiring pinouts matter. You don’t get second chances when you’re buttoning up a 722.6. Access the Factory Manual from AutoRepairManuals and get the specs that match what Mercedes used at the factory. Put it on your tablet or print the pages you need. I keep mine right on the workbench.