After a brief struggle with my parsimony, I have finally decided to buy original BMW transmission fluid. Sticker on side of gearbox was worn out, but it was of yellow color indicating that I needed MTF-LT-2 fluid. Local BMW dealer had it for MSRP price about $140 for 5 liters. It is a bit more expensive compared to everybody’s’ favorite Red Line MTL, which one could buy from for example OGRacing for just under $9 per liter.

The manual gearbox fluid change is really easy DIY project.

You will need the following tools:

• 17 mm 6pt socket
• Some ratchet
• 17 mm box end or combination wrench, 6pt is the best in my opinion since plugs made from some very soft metal and you can very easily strip plug’s flange if using open ended wrench.
• Torque wrench
• Some hand pump
• one or two feet of clear plastic tubing
• Floor jack or similar to jack up the car

First of all you’ll need to jack the car up. I usually just drive rear wheels onto ramps and jack up front of car with floor jack, then secure jack stands. Some people drive front wheel onto ramps and jack up the rear. I personally find it a bit dangerous since car can roll away once rear wheel s are off the ground and besides my E39 has rubber jacking point in the front and nothing except rear differential on the back that I could use as jacking point.

Find transmission under the car after car is off the ground and leveled. Read the label and make sure you are going to use the right fluid for you gearbox. Here is view of transmission from under the car.

Photo from BMW325i.NET

Before you remove drain plug make sure that fill plug is not seized. And definitely use either sockets or box-end wrenches to break seize. I almost stripped my fill plug flange when tried to use open end of wrench. Believe me it is very soft.

Here is what color fluid came from my gearbox after 52000 miles. I seriously doubt that it is healthy to have it in the gearbox for the life of car. Well I have to agree with thought that the lifetime fluid is most likely BMW marketing gimmick to attract more customers. It is very unlikely that BMW cares what happens to our cars after 50000 mile warranty and they will gladly offer us replacement transmissions for one forth of car price.

Once plugs are removed and old fluid drained. Replace drain plugs and torque it, on my BMW E39 car it is to 70 Nm. Using hand pump and plastic tube pump transmission fluid into fill hole until it overfills and it starts to leak out of the fill hole. Replace fill plug, tighten it to same torque as drain plug (70 Nm). Check for leaks and you are done.

One more thing, do not forget to lower your car on the ground.