OK, so I put the 997 up on blocks noticed two drain plugs on the pan, one about 4 inches above the other so I figured the higher one was the fill hole, so I took that out first, and about a quart of fluid drained out. Then I pulled the other plug and another 3-4 quarts came out. I started looking around on the transmission case for a fill hole but I found none. In reading I understand the transmission should be filled while the engine is running and then about a quart of oil is displaced internally and that is why when I drained the top hole, with the engine off, there was fluid above that level to come out.
IS THIS RIGHT?

 

Not sure what you mean about "top" hole. I don't own a Tip but video shows filling from bottom of pan. Are you sure you didn't drain the differential fluid?

 

Here's another video I found for a 911. Techs are using a flush machine though, so this may be of limited help.

 

No, as I stated, the two plugs are in the pan. The pan on this transmission has a sloping side, unlike the Boxster trans pan which appears flat on the bottom. The first plug you see on my pan is on the bottom of the "well", where the filter is, the second is about 6" away on the sloped section of the pan, creating about 4" of vertical separation between the two plugs. I can't imagine that this is not the fill plug, but it seems ridiculous to have a design where "fill to overflowing while running the engine" is the means of fluid change. I plan on making fluid changes every 24 months or so, not every 10 years, so I'm thinking of designing a fill port to replace the upper plug; We'll see; but if anyone else has an idea or solution, I'd like to hear it.

 

Here's an article I found on Pelican Parts. It's on a 996 but should be the same as your car. There's a picture showing the newer sump pan on 2002-on cars. Fill plug is the upper one.
https://www.pelicanparts.com/techart...sion_Fluid.htm

 

“I can't imagine that this is not the fill plug, but it seems ridiculous to have a design where "fill to overflowing while running the engine" is the means of fluid change”


German engineering does not design things hard or ridiculous to do because they have to, they do it that way because they can.

 

Here's a youtube video I saved showing the procedure. You may have already seen this on the boxster but it's the same idea. The pelican link is good too. Just fill until it drips... that's how you do the front diff, rear diff, manual trans fluid... etc. The additional step for the tiptronic is that you have to get it up to temp, cycle the gears, and then fill a bit more.

 

OK...so overflow while running it is. Otherwise it was pretty easy. The transmission filling guy at the factory must not mind getting leaked on...

 

OK. On the Tipt gear boxes, there is a factory oil fill port at the very top of the gearbox, way to the front (the nose) of the transmission. the plug is black (with a Mercedes star) and pops off the gear box. The fill port will take a 1/2 OD hose, which can be attached to a hand pump. This is how the factory fills it at the beginning,

You measure how much dripped out of the gear box and you put that same amount back in. Forget the "warm the engine up and fill it …" procedure. That is total frustrating garbage.
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Picture

 

Waving the BS Flag here - what if fluid level is low to begin with? You gonna short fill the transmission and call that good? If you're going to do this service you're better off doing it right. Handheld thermometers aren't that expensive and a decent scan tool (Blue Driver, iCarsoft, Durametric) will give you the fluid temp.

 

Thanks everyone for your links and advice. I wound up taking one of the M10 x1.0 threaded plugs to Home Depot to see if I could find some plumbing fitting to thread into the upper plug's hole, and I did, a 1/8 MIP brass nipple is perfect! I got one that was 1.5" long and my 3/8" I.D. translucent poly tubing fit snugly enough on the nipple, no hose clamp is needed. I cut a length of tubing about 4' long. On the other end I put a fitting that gave me the ability to use a small plastic funnel. I taped the funnel end of the tubing to an old tripod at about 16" higher than the fill port on the transmission, and I measured the height of the fill plug hole and taped off the same height on the vertical section of the funnel side so I would know when the fluid was exceeding the fill-hole height. I proceeded to fill the transmission.

Now judging by the flow rate of the fluid down the tube, I'd be careful if I were pumping it in under pressure, since there seems to be a lot of back pressure, which means if you blast the fluid into a sealed port like my setup, you may blow a seal by building air pressure inside the tranny case. Anyway it took me about 12 minutes to put in about 7 liters.

The great part is the ease of managing the overflow with this setup. So I started the engine and got the trans pan to temperature, ran the trans through R, 1 & 2 for a few minutes, and then simply lowered the tube and drained the "overflow" into one of the empty fluid containers. I recovered about 1/3L, I pulled the tubing off, unscrewed the nipple, and tightened the plug.

The Transmission shifts perfectly, doesn't leak, and no longer shudders during acceleration. All-told I spend about $130 in sundries, and I did a new pan gasket and filter as well...all from Pelican Parts. I wouldn't go 10 years like the advice seems to be, I'd probably do this every 2-3 years, and since I was quoted anywhere from $550-$1000 to do this at a specialty shop, this savings makes more frequent changes that much more appealing.

 

Your car, you do it your way. My car, I do it my way. I have the durametric and hand laser thermometer. Is still do it this way. I know my transmission. I know what came out, and I know what to put back in. This started when I took out 5 liters and can only put back 2.5 liters using the run the gearbox method. Just because it is not what the book says does not mean it's not correct.

 

Yes, I'm familiar with Teutonic punishment...🤣

 

Totally agree. This procedure was carefully designed for a reason, and I've never had a problem with it. It is a rare work day indeed when what comes out is EXACTLY what goes back in , and -please note: this is a common procedure for other German gearboxes eg ZF too. I do have a lingering annoyance for those that start off by saying "the manual is BS but my way is right..." or similar with no backup proof apart from some questionable failure ( user error ?) .. I agree - those with perhaps limited mechanical experience reading this thread please be circumspect about what you might take as gospel before tackling this task . HTH