Don"t spend money on transmission work until you try this!

Most of my driving is around town and my 300SDL is so smooth and quiet that the only I could tell that I wasn't always getting into fourth gear was at high speed when I noticed it on the tachometer. The car's mileage was a little inconsistent too. I assumed that eventually I was going to have to remove the transmission and send it off for an expensive repair.

Things became more urgent when it quit shifting into third!

It was time to start shopping for a transmission overhaul so I got on the phone and made a few calls. My first call was to John at Anaheim Mercedes where I was shocked to hear that a rebuilt transmission would be over $2,950 plus about $250 each way. John said that he was shocked too because they have gone up a lot recently and he suggested that I call the place where they send owners of older Mercedes for Transmission repair. I called Bob at J B Motorsports (818-996-4104) and was amazed at how helpful he was. When I told him that my car had an original transmission with about 150,000 miles on it that had been serviced regularly he told me that there was only a slim chance that it really needed an overhaul.

Bob told me that there are a couple of small screen filters in the valve body that usually plug up with debtis and cause the type of problems that I was having. He told me that I needed to drain the fluid, drop the fan and filter and remove the valve body. Then clean out the screens and put it back together.

There are 15 bolts that hold the front part of the valve body on. You unscrew them and drop the valve body and place it on your bench. Then you unscrew the 8 or 9 bolts that hold the back part on and it comes out along with the valve body plate. With the plate off, you unscrew 4 screws that hold the back section on to the valve body plate. In the back section there are two small screen filters which you can remove and clean with brake cleaner. They look just like the sediment filters on a washing machine hose except that they are much smaller... about 5 MM in diameter. When I saw that mine were plugged up with debris I knew I had found the problem.

Reassembly is the reverse of removal. You clean off the old plate gasket and install a new one, then bolt the back section on and then the front section. Then you torque all of the bolts to 96 inch pounds, reinstall the filter and pan and refill with fluid.

Here is a website that gives you an idea of what the transmission looks like.

http://www.w124performance.com/docs/mb/other/tranny_722_repair.pdf


The job cost $8 list for the gasket and and I spent $7.50 for fluid to replace the fluid I dumped out. It took a couple of hours. The results are simply amazing. The car is really fun to drive now. Not only did it fix the upshift problem, but the transmission is smoother and more responsive than ever. Based on the fact that this job is easy and inexpensive, I would recommend it to anyone who has an older Mercedes that is not shifting well. Also I would recommend Bob to anyone who is facing more serious transmission work.

What is really amazing is to think of how many folks shell out 3 or 4 grand to get their transmission working right when this is all it needs.

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Tom Hughes
St. Louis
84 300SD
92 300D
86 300SDL

Great info, Thank you.

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Master Computer Engineer, A+, Network+, MCP/MCSA/MCSE 4/2k/2k3 - Messaging, MCTS, MCITP, MCT, Brainbench, ICDL and starting Ph.D

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anyone else done this? Is it still running well?
tonight on my 83sd it would downshift from 4 to 3. About 20 miles later, 3 stopped working. It acts like it is in neutral. Back to 2 and goes good. and if you power brake it, you can get tire spin.
So it is a 3 and 4 gear issue.
Still searching for answers
Thanks

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83 300SD Dark Silver Dark brown inside

that is a great trans article but its the incorrect info - but yet they are similar the 300D is different BUT my guess is the clutches are gone and or the seals are brittle ( like stone ) and has led up to this the guy from Washington offered to help you HELLO -- the kit is around 300 bucks we in my shop in jersey always for the diesel cars replace the valve body plate with a re program kit ( trans go ) it fixes almost every thing that is wrong with the 123 trans - reason being it relies on the modular pressure to adjust both the when and how it shifts the info sent up above is the later unit and it has a boden cable for the when it shifts, and is way easer to set up when done - take the unit out and let the guy take it apart high millage diesels or gas cars always do this 150 to 200 thous miles depends on city or highway driving -- jz