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If your modulator is working ok, but leaking transmission fluid, you may only need to replace the inexpensive oring ( o ring ). You do have to be careful when removing the modulator from the transmission. For instructions (available separately) see related products below.

Custom ordered for a better fit than original! special Oring seal for the bowden cable housing where it connects to the right side of the automatic transmission. This is a common leak area and you may be fooled into thinking it is leaking out of the pan gasket.

The plastic shift bushing is a very common part that needs to be replaced on older Mercedes. Can you believe it is the exact same part that was used on all models for over 25 years! It is an inexpensive part that can cause big problems if it breaks out.

This unique kit will allow you to hook up a 30 in HG vacuum gauge between your vacuum control shifting valve (VCV) and your transmission modulator to test the VCV for proper function and to tune it for peak shifting performance.

9/2025 Update: Green and Red Modulators are NLA, and we have been informed that they will not be remanufactured. But, do not panic! You may have heard that you must replace your 1981 to 1995 transmission modulator with the correct color top.

If you are interested in this transmission, please do not try to check out. Contact us via email to arrange payment and pickup. Please note: I will only sell this transmission to a knowledgeable W123 Mercedes turbo diesel enthusiast who plans to install it himself.

This seal is a common leak point on the front of 722.4 transmissions, primarily due to age, which causes the seal to harden. This is an easy install once you remove the transmission from the car.

Only one available. This is a quality aftermarket part. Study the picture carefully to make sure that you know which band you are ordering.

Why rebuild a 722.3 valve body? Some may have told you just to "leave it alone." It can be a little intimidating, especially if you have visions of all kinds of springs, balls, and little valves flying all over the place when you take it apart. Watch the video below for a short overview.

Why have a separate tester just to measure the full pressure running inside the transmission? For this test, the pressure can reach up to 240 psi and can go higher if there is a restriction. This requires a special gauge and hose that can handle the pressure.

Since new B2 pistons are no longer being made, repairing your old one is your only option. The large outer sealing ring will not work with the very early piston version, which has a narrow sealing ring on the outside of the piston. Your piston MUST have the wide ring as shown.

If you try to open up those clutch drums without this tool you WILL be frustrated!  You may get them open, but trying to put them back together is something else! If you need instructions or other parts see related products below.

Tired of the "old ways" of changing fluids in your car? Watch the video below to see how to do it fast, with less mess and stress-free.

Introductory special. Full video instructions for both repairing pipe leaks and reducing chaffing are included (on a 1983 300D). This is now becoming a bigger problem as these diesels age. Inspect your cooler lines soon!

These are getting harder to find in good used condition. Replacing a valve body with a known good one is often an easy way to troubleshoot a problematic transmission. Fluid inside is clean and has been stored in a sealed bag since removal.

This is one of the most common leaks we have seen on these transmissions over the past 25 years. If you are discovering big puddels of red transmission fluid on the ground at the front of the transmission I can almost guarantee it is the front pump leaking.