Mercedes W123 Manual Gearbox Problems
Hi everyone,This is my first post on the forum. I've been lucky enough to have taken on a 1980 W123 saloon. I don't have too many details as yet but as far as I know it's a 200 automatic petrol.The car's been sat a few years in a dry garage so I want to get a few servicing parts ordered before I pick up the car so I'm ready to get to work straight away.
Mercedes W123 Coupe
Front and rear discs and pads will be ordered shortly along with oil, fuel and air filters and spark plugs. I think I will also do a coolant flush whilst I'm at it along with an ATF change.A few questions:1.Is there a filter in the gearbox/sump? Where can order one? Eurocarparts don't seem to do it.2. What fluids are recommended for each of the above? I don't have a service/owner's manual.Engine oilATFBrake fluidCoolant3. Should I remove the old fuel (how)?
Apparently these were designed to run on leaded petrol. What do people use now? Do you use a lead additive, what is it and how often?4. Any other suggestions for things that would need looking at? I have a new battery to go in.Any help/advice would be appreciated.
Diff oil will be about 1.1 litresdiff is easy to change. See here:and here for a non-ramp method:, jacked up the rear passenger side of the car, supported on axle stands, got under and undid the filler and then the drain, and drained the old oil out. I then cleaned up both plugs and refitted the drain. I then filled up with the oil. Then i lowered the car to the ground so its level and let the overfill flow out. Then i jacked it back up again to fit the filler plug. Both tightened to 50 NM and job done.this overfill method is great if you dont have the means to raise the car up level.
The oil comes in 1 litre bottles so you have plenty of spare to waste (car takes about 1.1 litres i believe). I also managed to fill it using the oil bottle it came in squeezing it just above the exhaust and then the final amount via a small oil can i got from PoundLand.
Many shift related problems can be solved without tearing down the transmission. Particularly on diesel automatics, an external control component or loss of vacuum could be the problem. Kent has developed a number of kits and manuals that will help you solve your transmission woes.
As diesel automatics age the problems become more complex and the solutions more challenging. Automatics in gas cars can also have problems but they are not as complex. When 'de-bugging' an automatic transmission shift problem you need to go about it in a systematic manner. Just throwing money and parts at the problem will usually not work.Before assuming the worst I recommend you do the following:.
Don't spend any money on expensive parts until doing a proper diagnosis. The manuals and test kits I offer will help you isolate the problem. If you are having a shop work on your transmission be extra cautious. Get more than one opinion if seeking help from a transmission shop. Watch my on demand video on Intro to Troubleshooting Automatics - this will help you decide if you want to fix it yourself. Think outside the transmission first.
Many problems are external. Follow the sequence belowBefore considering a replacement transmission read my diesel transmission tuning manual. It will walk you through 8 phases of diagnostics and repair to get your transmission shifting properly.
Mercedes W123 Manual Gearbox Problems List
You may be surprised to learn just how many problems can be 'adjusted out.' This 125 page transmission tuning manual and associated repair kits will help you 'fix it yourself' and possibly save hundreds of dollars.During the time I have spent testing and tuning transmissions, I found a number of products that are easy to install and can help improve transmission performance. Sometimes a $3.00 part can go a long way to fixing a BIG problem.Please click on any of the related products listed to learn more. Recommended products.