transmission oil change; 911 tool kit to the rescue

[Carrera Kid]

I finally got around to changing the transmission oil in my '87 Carrera. It took me a while to find Mobil 1 gear oil.

So I put the car up on the hoist and discover that I don't have the proper size hex wrench for the drain and fill plugs; it's a 10mm hex and the largest I had was an 8mm. So I found a bolt, the head of which was the right size for the hex in the plug, and I welded it to a scrap piece of metal strap. Of course the plugs are so tight that I snap off the bolt at the shank. A little cursing. I take a spare 8mm allen wrench and weld a nut to the end of it; looks like a large lump of metal at the end of the hex wrench at this point. I go at it with the grinder until it nicely fits in the fill plug hex. The plug is very tight so I apply a little persuasion with a hammer and snap off the nut from the wrench. A little more cursing at this point and I give up until I can get the proper size wrench. I wander inside and read the section in my "911 projects" book on changing transmission oil. It says the the older trannys have a 17 mm hex and the newer ones (the G-50's) use a 19mm socket. Hmmm, something weird here since mine sure looks factory.

For some reason I suddenly think of the tool kit that came with the car and remember how complete it seemed to be. I pull the factory tool kit out and, sure enough, there is a nice new-looking 10mm hex wrench. This one didn't snap off and worked like the proverbial charm.

So for those that have transmission drain and fill plugs with wrenching features that seem to defy what the books tell you, check the factory tool kit. Oh, also for those that haven't done this before, 3 bottles of Mobil 1 gear oil (1 US quart each) is just the right amount.

Rick

[nvnovrts]

brilliant.

[lupin..the..3rd]

If you used the standard Mobil 1 gear oil quarts from your FLAPS, you might want to change it again. That is a cheapo oil, and is NOT Porsche approved for any G50 transmission!

If you want a Porsche approved G50 transmission oil made by Mobil, there is only one choice: Mobil Delvac 75w90. You can sometimes find it at truck stops, but I've always had to order it online. Delvac is not available in quart size, only gallons. Delvac is not the same thing as "Mobil 1" from your FLAPS!!

Personally I prefer Redline 75w90ns gear oil in my G50. It has smoother cold weather behavior than the Delvac but costs about the same. Also it's readily available from most racing shops. Either one of these is a good choice:

Redline gallon: http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=PEL-58305&catalog_description=Red%20Line%2075W%2F90%20Non-Slip%20GL-5%20Gear%20Oil%2C%201%20Gallon

Mobil Delvac gallon: http://www.lufteknic.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=Mobil75-90delvac&Category_Code=lubricants