Are these two gear oils the same?
 

I took my GT4 to an independent shop and asked them change the transaxle oil. I told them the transaxle takes Mobilube PTX 75W-90. I looked at the Porsche part number on the shop's invoice and it was 000 043 305 49. That number is for a 1 liter bottle of Porsche branded 75W-90 transaxle oil, but there is apparently a different Porsche part number for Mobilube PTX 75W-90 in the Porsche parts catalogue. Photos of the two bottles on the internet look different as well.

The last time I had the oil changed I ordered it from Sun Coast and it came in white 1 liter bottles labeled with the Mobil logo and they say Mobliube PTX 75W-90 on the label. The oil that the shop used this time came in a grey/silver bottle that has the Porsche brand on it. I was concerned that the oil that was put into the car (the stuff in the grey/silver bottle) may not be PTX, so I called PCNA to ask, and they just passed me on to my local Porsche dealer. The parts guy at the dealership told me that the two part numbers are for the same oil but one is for a 20 liter container and the other is for a 1 liter bottle. Suncoast told me that they buy the 20 liter PTX and put into smaller 1 liter white bottles to sell to their customers. The Suncoast guy said he doesn't think the oil that corresponds to the part number ending in 49 is PTX but he cannot be sure. It feels like something does not line up right with all of these pieces of information, but I am running into a dead end. Any info anyone here has on this issue would be appreciated. I just need to decide whether to have the fluid changed again before my next DE to ensure the correct fluid is used. The shop has graciously offered to change the oil again free of charge using PTX from Sun Coast, but logistically it will be difficult for me to get down there before the next event.

The stuff from Suncoast was put into the liter bottles by Suncoast and then they put a laser printed label on the bottle. Back then Porsche wasn't supplying small bottles. I think now you can get it from the dealers in a legit 1 liter (or quart, not sure) bottle. Hope this makes sense...

FWIW, I did some research earlier on the topic here:
https://rennlist.com/forums/showpost...0&postcount=40
There is a wide range of fluids rather equivalent. Higher viscosity numbers typically provide higher shear strength films which is beneficial to wear, but the limit is when the shifting becomes difficult, particularly when cold.

In July 2018 I purchased Mobil Lube PTX 75 90 from Sunset Porsche in Oregon. I spoke with the parts guy and he said they get it in large containers and would be happy to break it into liters for me. It arrived in unmarked black quart or liter containers. They charged me $30.11 per container. Pretty good deal I thought.