Inverted 997 tranny oil level

#1
I researched but was unable to get a definitive answer. Its my understanding that a Porsche 997 transaxle takes 3 quarts of oil. By inverting the transaxle will it now require more oil for proper lubrication??? Thanks
 

Randy V

Administrator
#4
You might want to share that answer here. That way it may be found in a search by someone else that may need that info in the future!
 
#5
If I was having a to answer the same question, this is how Iwould go about it.
I would install a clear plastic drain tube that was longenough that I could loop around and over the top of the transaxle wheninstalled in its standard orientation. Iwould then fill it and record the height of the oil relative to the lower gearcluster shaft in the gear box. I amassuming that the oil level sits below the centre line of this shaft. When in operation the gears pick up the aeratedoil as the splash through the bottom of the case. I would then drain the oil, flip the case andinstall a similar drain line in the inverted box. I would re fill the box until I had achieveda similar coverage of the new lower shaft. The only thing to watch out for may be if the ring gear now sits in alarge depression and would be likely to sit in a pool of oil, causing excesswindage, drag and potential for hydroscopic pitting.

Anyone care to comment on that methodology?
No idea if its right, however getting an answer from someonelike CMS does seem like it’s a better idea.


Ryan
 

Howard Jones

Gold Supporter
#6
Ryan. I agree that's a good way to determine how much oil is needed. Then I filled the cooler, filter, and the lines and measured the amount in them and added to the tranny fill amount. In my car (G50) the total came to right at 1 gallon. CMS is where I got my G50 and I highly recommend them. I 'm sure they have a preferred fill volume.
 
#7
CMS said it should work but I did not get that feeling and wanted confirmation. I contact someone who a few months ago finished his build with a Porsche 996 transaxle. He said he used just under the recommented 3 quarts of oil and plugged the Vent. His tranny is working great. All I need now is to find the way of properly plugging the vent and good to go. Thank you all for your input.
 

Randy V

Administrator
#8
Thanks for sharing that George!

As I recall from a previous thread, the key concern was that the counter/lay shaft is normally submerged, but when inverted, it is above the level of oil if filled to normal capacity.. I don’t recall where we left off with that conversation though...
 
#9
I spoke to Chris from Active Power who builds many of his cars with inverted Porsche transaxles. Use vise grips and remove the vent on top of the tranny by moving it back and forth until it pops out. Then use a 1/4 inch pipe tap that will fit perfectly. Use grease on the tap while tapping the hole to keep the aluminum slivers out. Then use a 1/4 pipe plug to seal the hole. Then drill a 1/8 inch hole on the oil drain plug that now will become your new vent. I just did it on my tranny and I’m good to go.
 
#12
Are some just flipping the 996/997 transaxle without adding an external oil pump? If so, has this been shown to be reliable? Any difference if you plan to run the GT40 on the track?


Thanks1
 
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