Transmission Fluid

[Keen]

1989 560SEL

I have noticed a small leak from my transmission on the garage floor and would like to confirm where and how one should top up the fluid. Must it be done from the undercarriage or can it be accessed from the engine compartment. Please advise with as much detail as necessary as I am relatively new to this.

Many thanks.

[rschleicher]

You add ATF via the transmission fluid dip-stick tube. Since the opening is small, it helps to use a plastic straw or maybe a swizzle stick to guide the stream of fluid.

You want to add just a little at a time, and of course check the level with the engine running (in Park, at idle). Your owner's manual describes this, I believe (my car is a 1991 420SEL, so it has basically the same owner's manual). The full line on the dipstick is correct for a warmed-up transmission, the manual may say something about how much below the line it should be with the transmission cold. But, in any case, the engine must be running, as readings with the engine off are completely wrong.

As for your leak, you may want to check the two pressure hoses that run from the transmission to the transmission fluid coolers on either side of the radiator. There is a hose on both sides of the radiator. Each hose is about a foot long or so, and it is pretty common to develop slow leaks on these. They are a little exposed - the replacement hoses have a protective metal coil around the rubber part of the hose. You can replace these without draining the transmission, as long as the engine is turned off when you disconnect them.

Bob Schleicher
1991 420SEL, 172,000 miles