July 01, 2020

Always Identify These Valve Bodies BEFORE You Start a Transmission Rebuild

Andrew Jessiman

Mercedes 722.6 Valve Body

Unless you’re an expert on a particular transmission, don’t wait until you’re about to install parts to verify exactly what valve body is in there — they aren’t always model and VIN specific. This is a lesson many DIYers and even professional rebuilders learn the hard way. Some transmissions, like the Mercedes 722.6, can have up to seven different valve body options!

The Sonnax tech team gets calls almost daily from folks frustrated with a build because they didn’t drop the pan and properly identify the unit BEFORE they bought parts. Maybe you’ve been there yourself. A job you thought would only take a few hours is now off the rails while you scramble to figure out what unit is actually on the bench, what parts it needs and whether a local distributor even has them in stock. For shops, this often means a vehicle is taking up precious space on a lift until replacement parts arrive. DIYers face a vehicle on jackstands for days in the driveway while they hunt down the right parts and then wait on shipping.

As with so many projects, a build isn’t just about installing parts, it’s about the preparation. If you aren’t 100% sure what to expect when you drop that pan, set aside time to do that so the vehicle isn’t off the road a lot longer than you planned.

The following units are the most critical to identify when choosing the right Sonnax products for your build. More free valve body identification guides for dozens of transmissions are available 24/7 in the Sonnax tech resource section.

Aisin AW

Allison® 1000, 2000, 2400

Chrysler 40TE/S, 41TE/S, 41AE




Mercedes 722.6


VW/Audi 09G

ZF ZF6HP19/26/32 (Gen. 1), ZF6HP21/28/34 (Gen. 2)

Once you’ve identified the valve body, also allow time for finding the products you need. This Sonnax distributor map is a great way to see who in your area offers transmission parts and remanufactured valve bodies. One location may not have everything in stock, so the more nearby distributors you can reach out to, the better your chances of getting parts so the vehicle is back on the road fast.

Need more help? Contact the tech team anytime for comprehensive assistance with Sonnax products.

Andrew Jessiman is a Sonnax product support representative. He is a member of the Sonnax TASC Force (Technical Automotive Specialties Committee), a group of recognized industry technical specialists, transmission rebuilders and Sonnax technicians.

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While Sonnax makes every effort to ensure the accuracy of technical articles at time of publication, we assume no liability for inaccuracies or for information which may become outdated or obsolete over time.