Please can someone kindly explain this ?
I have recently purchased a transmission service kit for my L405 3.0 v6 diesel from ZF transmissions, it came with full instructions that I followed to the letter, new filter, filler plug sump bolts and 7 litres of oil.
I drained the old oil, approximately 4.5 litres came out and then replaced the oil pan and filter. I then refilled the transmission with 2 litres of lifeguard fluid 8 until it ran out of the filler hole, I then waited until the oil temperature was 43 degrees c before following the ZF instructions. Starting the engine running it at 2000 rpm for 30 seconds, selecting P, N, R. D, then manually selecting D1, D2 etc. I then topped up the transmission while it was still under 50 degrees c.

I only managed to get another litre of fluid into the box before it was overflowing, a total of 3 litres, now I believe the system holds a total of 8.1 litres, only 4.5 came out and I could only get 3 litres back in to the transmission, please can someone explain what is going on and am I safe to run the car?

Quote:

..... 2000 rpm for 30 seconds, selecting P, N, R. D, then manually selecting D1, D2 etc. I then topped up the transmission while it was still under 50 degrees c.

Thanks for your reply, no I didn’t keep it running during the last fill, whoops!! I’ll give it another go while it’s running and at the correct temperature.

You can only get 4-5 litres replaced using the method you described. This is the standard service.

You can have a power flush completed that replaces nearly all the fluid. Dan. 🇨🇦 2013 L405 5.0 SCV8

Thanks for the information, I feel a little better knowing this is normal.

When I did my transmission oil change last year I got 4.5l out and added 4.6l back in. My kit came with 8l of ZF branded oil so I figured that I could buy another 2l and miss the sump/filter change and just do a second oil change at some point. That way it'll get to 75% changed oil which is better than 50% changed oil.

Unless you drain/flush the oil cooler and the lines running to and from the cooler you'll never get anywhere close to a 100% change out.

Thanks everyone for your replies. I did the final fill this morning. The temperature from cold was sat at 26 degrees c, I waited until 30c and went through the procedure again, this time I left the engine running and managed to get a further 1.5 litres in to the transmission, a total of 4.5 litres. Thanks to your help I’m happy that everything is ok but I will do another oil change in the near future.