BMW transmissions and differentials require the use of specific fluids. The fluid recommendations not only vary from year to year and model to model, they may also vary from component to component. Changing the engine oil is a relatively straightforward task, however due to their physical location, the transmissions and differentials will require the use of some means of transferring a lubricant from a container into the fill hole. For example, on later model E36 automatic transmissions, the transmission fluid fill hole is a recessed cavity accessed from the bottom of the sump.
Being properly prepared is far better than having your car on jack stands, the fluid drained into a drain pan, and several containers of fresh lubricant at your finger tips, and no way of getting the fluid where it needs to be.
A hand pump or siphon gun will work well for transferring a fluid from a container into an inaccessible fill hole to properly top off or refill the fluid level.
Whether filling or topping off, always place a suitable drain pan under the fill hole to catch any fluid spills that may occur while working on the vehicle.
The following hand pumps are available from area retailers:
The Sta-Lube® fluid pump fits the gallon containers of Sta-Lube® lubricants and also fits the NAPA® 1 gallon windshield washer fluid containers.
Attach the fluid pump to the fluid container, or if necessary pour the fluid into a clean container that will fit the fluid pump, and simply pump the fluid into the fill hole with the pump.
Another solution is to use a siphon gun, also available through an automotive parts vendor. The fluid is drawn from the fluid container into the siphon gun, and then transferred from the siphon gun into the component.