tonyC230

I don't know if BabyBenz got the fluid change done but heres my 2 cents worth. I found out that MB Factory oil is 75/80 gear oil and that the factory stuff is sold in half liter size container for an arm and a leg. Why would I put factory gear oil in my car if I wasn't happy with the shifting. I tried Royal Purple Max Gear 75/90 and did not find any difference then factory. I then went to Redline MTL that is a 70/80 synthetic gear oil. It worked best and even better when cold compared to factory stuff. My car ( 02 ) calls for 1.2 liters but I drained out the fluid that came with the car and measured the volume and found 1.5 liters. That is what I put back in. I also have a Miata with a 6 speed and it takes 2 liters of gear oil. The Benz tranny has a drain bolt with a magnet like all cars and a filler on the side that should be designed so that one can not overfill the tranny. My Miata does just that. The Benz fluid is below the filler. I tried to check with my finger but could not touch fluid once I filled it with 1.5 liters. I wonder what would happen with the shifting if one filled flud to just below the filler bolt????? Hope this helps PS. The gearbox is made by Getrag (GM) not Mercedes!!!

GDawgC220

I remember reading one of your threads about that.

Purple Max is a good gear fluid. I just replaced mine with Motul 300 75w-90, very good stuff. You can find it for $13 per liter online here:
http://www.4induktion.com/catalog/pr...products_id=88

My 6-speed unit takes 3 liters of that stuff. You can use the directions as mentioned in one of my earlier posts, regardless of what fluid you get.

alpinweiss

I always recommend changing transmission and differential oil at about 30,000 mile intervals. Again, the reason is mostly to get out metal shavings, dirt, etc.

For your C230k 6-speed, Mercedes uses a synthetic manual transmission oil. It is sold by the liter bottle at your dealer, for about $30 (gulp). You will need to buy 2 liters. You will also need two allen wrenches, a 14mm and a 17mm.

Your car was probably originally factory filled with 1.5 liters. The service manual (and TSB) recommends refilling it with only 1.2 liters for easier cold weather shifting. This will be significantly below the filler plug, so you would have to measure the oil if you follow the updated recommendation. I do not see any warnings that 1.5 liters will harm your transmission though, so use your own judgement.


The clearance between the fill plug (14mm) and the transmission tunnel is fairly tight, so use a short allen socket. A Hazet 985-14 socket will work; I am sure others are also available.

The rear differential uses a different oil, so don't get them mixed-up.

tonyC230

I was told about the lower amount of fluid (1.2 liters) for better shifting but that doesn't make sense to me. That lower amount of fluid will have to slash around pretty fast to lubricate all the gears and bearings so I will opt for the 1.5 liter amount. Synthetic fluid should be fluid down to minus temperatures that I wouldn't see anyway. My Miata 6 speed takes 2 liters and don't think it is any bigger then the tranny in my C230. By the way, I tried the lower amount (1.2 liters) for a day and did not find better shifting. Guess Mercedes changed the gearbox on the 230's in 04 I believe. Someone at headquarters must have tried out one of the earlier ones and realized that Getrag didn't do a good job with all that linkage so they updated the newer cars with one shift rod like Mazda has had since 1989 in the Miatas. Mercedes aren't big on Manual gear boxes. I think BMW also get manual bear boxes from Getrag but they must follow up on thier operation as the Bimmers shift pretty good.