View Single Post
      11-25-2021, 10:31 PM   #4
First Lieutenant

Drives: 2014 M235 RWD
Join Date: Jan 2017
Location: Minnesota

iTrader: (0)

I recently did mine, and it was the most annoying transmission fluid change I've ever done.

Access to the fill plug is really tight. It's right up against a frame rail. A regular socket fits, but you don't have clearance to get a regular ratchet on the socket. Not sure what tool would actually fit, but I had to cobble together two wrenches on the 8mm socket alone to get enough leverage on it. A tiny 8mm on the stub of the socket hex, and larger wrench on that one. You also only have about 3" of clearance out from the fill plug to the hot exhaust pipe. And since you have to run the engine during filling, it's going to be hot.

Filling is a pain too. You will definitely want a bent metal pipe to access the fill hole, and a high capacity (several quarts) filling system to push the fluid in. I was using a half-liter syringe, and that was just a messy disaster. Better once I built an appropriate bent metal fill tube, but still a pain.

And remember, you need to bring it to total fill with the engine running, and while doing the gear change exercise, and while monitoring temps, and get this all done before the transmission gets too hot. The fill temp is relatively low 110F. If you're doing this on a warm day, that temp happens fast. I had to add about 1.5 L after the gear exercise to bring it to final level.

I also had issues with the gear exercise. Online sources say to keep the brakes on, and don't let the wheels turn while moving the gear shift from reverse/neutral/forward and then through the gears. Well, the car won't go beyond 2nd gear unless the wheels are turning. (Unless there is some trick I'm totally missing.) And if you do let the wheels spin, you have to put it in DSC off or it apples the rear brakes. It still wouldn't go above 6th for me, and the ECU was really complaining about a driveline failure. I suspect if you put it in 'roller mode', aka dyno mode, that wouldn't happen. But yet another thing to fiddle with if you do that.

Oh, and I almost forgot the stench of the ZF Lifeguard fluid. Get any rags you use to sop up spills (and you will be dripping all over, and cleaning out pans since the fill literally has to spill out when it's done), out of the garage or into a sealed container. It smells worse than differential fluid.

All in all, I'm not sure I would do this myself again. Having a full lift would help a lot, as would a better fill system. An extra person to do the shifting and monitor the trans temps would also help. And I would definitely need to find a better wrench to fit the fill plug.

Last edited by ggggbmw; 11-25-2021 at 10:40 PM..
Appreciate 1