Got home after taking a quick soon for breakfast and running a few errands. Operating temps are way higher than “fill check” temps, so I had to wait a while for the fluid to naturally cool. This took forever.
Removing everything was easy and relatively simple. Bottled up sun be fluid mid-drain for oil analysis. This fluid stinks.
I cleaned all the surfaces and wiped down the electric pump/motor looking thing as it has some black film on it. Maybe metal particles? I could see some sediment in the old pan.
While buttoning everything back up, this is where I had a heart attack. I was double checking the torque on the last bolt, center rear and it started giving way. Odd. I couldn’t get it past 8nm and it just kept turning. I backed out the bolt, looked fine (but not a lot of light available), so I put it back in and started wrenching again. Same thing. Gets to 8-9 and starts to give. Suddenly, snap. F. I look in the hole and thank goodness the broken piece appears to be loose. I don’t know how this ever happened, since it should be stuck, but I’ll take it. I got a precision screwdriver and was able to use a tiny socket and back the bolt out. With a tiny drill bit and a small Phillips, I was finally able to get it backed out all the way. Found an old pan bolt that was clean and appeared in good condition, chased the threads, and put it in. Torqued to 10 and everything looked fine be. Checked the torque on the drain cap. 8+1. So… 9nm? Ok. Odd. But torqued to 9. Done.
Now for the fill. I dump all 7L of the ZF fluid into my pressure filter. Connect my compressor and started filling until a small trickle started coming out. I checked and still had 3L left in the power filter.
Start the car (it’s still on jackstands), with foot on the brake, I try to run it through all the gears, but it won’t stay in 2-8, probably because I’m not moving. Spent a few seconds in R, then back to N. Fluid heats up really fast. At 55 already. Maybe I had too much left over heat. Anyway, I go watch some TV to let it cool more. At 48C, I proceed to do my final fill. I was only able to add another ~0.5L before the fluid started leaking out again. I checked the level of my car; it was fine. So I tightened everything up and web by foot a drive around the block. Silky smooth. No issues.
So now I’m thoroughly puzzled. Was I supposed to put the transmission in service mode? I didn’t see any function like that in Protool. I've read that a drain and fill will use about 5L, but a pan change should need closer to 7L. However, I only used 4.5L. ???
I put the old fluid back in the old bottles and sure enough, about 4.5 L.
Did I miss something here? Why do I have 2.5L left over??
I just realized that I didn’t fill while the engine was on. But then again, I only drained 4.5. I basically filled what I drained.
