[kkasson]

I just changed my transmission fluid and I thought I'd post some tips that might be helpful for anyone else about to do it. The old fluid had 92k miles...it was dark but it didn't smell burnt or damaged.

1) I've seen a lot of people say they lifted the car and put a level on the transmission pan. This is not the way to do it. I noticed the pan slants downwards a bit towards the back of the car...the service procedure is made for the car to be on a lift, and on a lift the lift arms support the jack pads. So you should make sure that each jack pad is the same height off the ground, and then the pan will be positioned correctly to fill it.

2) The 30 to 50 degrees C filling temperature isn't very hot at all. If you're doing it by feel without a scan tool, the pan should just barely be warm. If it feels at all hot to the touch, then it's probably too hot. I first filled mine at about 70 degrees....when I checked it with the scanner and saw that it was at 70, I let it cool down for about 2 hours and then I filled it again. It took another half quart at that point, so it does make a difference.

3) I used a transfer pump to fill my differential and it was messy and difficult to use. So for the transmission I got about 5 feet of 3/8 inch clear vinyl tubing from Home Depot and zip-tied the end of the tubing to the transmission mount. I pulled the rest of it up and zip-tied it to the door handle and put a funnel in it. The tubing fit right into the fill plug, and I could stand outside the car and pour in the fluid.

The fill plug is a little bit higher than the side skirt, so a bit of the fluid pools at the bottom of the tubing. I first poured about 1/10th of a quart through to flush out any dust or dirt that might have been in the tubing, and then put the end of the tubing inside the fill plug and started filling it. I had to pour really slowly or the funnel would get filled up, but there was no mess and I could pour just exactly as much as I needed.

I zip-tied the tubing to the driver side door, which meant I had to go in the passenger side to turn the engine on and to shift through the gears. If I did it again, I might try to route it to the passenger side to avoid that. I was a little worried about putting vinyl tubing in the hot transmission, but the maximum operating temperature of the tubing is 80 degrees C and the transmission was no hotter than about 75 degrees.

4) The drain and fill capacity is somewhere around 4.5 quarts. Dropping the pan takes about 6, so that leaves 1.5 in the pan and in the filter which seems about right. It's probably a little less than 4.5 because that includes what I used to flush out the tubing and the fluid that came out of the fill plug when it was full. It took about 2 quarts with the engine off and 2 more with it on. But like I said above, the transmission was too hot at this point so I let it cool down and then added the last 1/2 quart when it was at about 40 degrees C.

Overall it was much easier than I anticipated...I spent about 2 hours on it trying to go slow and examine everything as I was doing it. I've dropped pans on other transmission before but I hadn't dealt with any without a fill plug on top, so I wasn't sure what to expect. I think running the tubing up to the door handle made it easier than it would have been trying to use my harbor freight transfer pump.

It does shift better now. It wasn't shifting bad before, but it was starting to feel a bit jerky. It's a lot smoother now...the 2 to 3 shift is still a little rough, I'm hoping that another drain and fill helps with that. I plan to drain and fill it again in a couple weeks, and then drop the pan after that. I used Valvoline Dexron VI, for anyone interested.

[Riick]

Every 6L45 car should have a transmission service every 50k miles, that's per General Motors. Two gallons of Maxlife Dexron VI and gasket/filter runs $80 and you shouldn't pay more than two hours of labor at any shop (roughly $160) to have the work done.

Lifetime my ass.

[kkasson]

Yes; the 6L45 is used on the Cadillac ATS, and the higher-torque 6L50 is used on some other GM vehicles. GM recommends 100k miles for normal service, or 50k for severe.

I did my second drain and fill today. I decided to lift the front end a bit higher after the fluid stopped draining to try to get a little more out of the pan this time. I got maybe 1/3 quart or so more by doing that.

When I refilled it this time I had the metallic tapping noise that was mentioned in a couple other DIYs. It was pretty loud, I could hear it inside the car and out. I shifted through all the gears a couple times and I revved the engine a little in park and it didn't go away. The fluid level was correct, so I decided to put the car back on the ground and try to drive it. It went away almost instantly after the car started moving...my guess is it sucked in a little air while I was filling the fluid and it just took some movement to get the air bled out.

Again I'd highly recommend using a scan tool to check the oil temperature when refilling. It took a few hours to cool down even with a fan blowing on the transmission pan. I took a few pictures this time of how I connected my plastic tubing...I tried to run it to the passenger side this time so I could use the driver's door but it was much easier to just go to the driver's side again.

It shifts a lot better after the second fluid change. The 2/3 shift that was still a little rough is smoother now. The fluid that came out was pretty dark again...I'm expecting that next time I drain it the fluid will be dark with a bit of the red showing through, which will mean that at that point the fluid actually in the transmission will be fairly clean.

[BashShah]

This thread says a lot about the 2-3 shift issue.
So I gotta do a few drain and fills....hmmmm.
I used zf OEM oil.

What are you guys using?

[kkasson]

Originally Posted by DarkNemesis

This thread says a lot about the 2-3 shift issue.
So I gotta do a few drain and fills....hmmmm.
I used zf OEM oil.

What are you guys using?

I have the GM so I didn't have to deal with it, but from what I've read Lifeguard 6 appears to be exactly the same as Mercon SP. I have a friend with a 325xi with the ZF transmission and I plan to use SP for that. Someone sent in unused samples of both fluids to Blackstone Labs and they concluded that they're nearly identical. Ford uses the same ZF transmission on some of their cars, so whatever fluid they're using must be acceptable for it.