So a little back story first. I picked up my '99 A4 Quattro back in October and I just finished paying it off. The previous owner seems to have kept it in decent shape but was lacking receipts for anything other than some glass and having the timing belt done. While I was doing the rear wheel bearings I noticed that the rear diff looked like it had leaked oil from around the drain plug but the rear end is still whisper quiet. Now to my question, what is the best gear lube for the rear diff and the manual transmission (brand and weight)? The reason why I have had to start my own thread on this is because the Haynes manual says 75w90 for the transaxle and SAE 90 for the rear diff, but people on here state the opposite. Also I know an Amsoil distributor so I could pick up that for cheaper than normal. Any help is appreciated so thanks in advance.

James

 

I had a thread over at the Zine about this. Read through the entire thread. I ended up going with Amsoil, shifts are much smoother. Moral of the story from that thread was dont use GL-5, it requires GL-4 fluid.

Change your transmission fluid......

 

Thanks for that link. I had no clue that there would be a difference. Did you run the same weight in the transmission and differential? And where would be the best place to find the security bit because Ebay is turning up nothing right now?

 

If you give me your VIN i can tell you exactly what it is.

 

WAUED28D3XA221557

 

Here's the drain plug bit I bought. Worked like a charm, solid quality. The seller is away until the 27th though.

eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices

and yes, the same weight in both. I have yet to swap the rear diff out for the amsoil, but I also took seerlahs advice on the amsoil sever gear 75w-90. He's well known for help on those boards (Although an amsoil fanboy, you cant deny the quality of oil)

 

Amsoil works for me.The AME I apprentice under is a distributor so I can get it for a steep discount. Thanks again for all the help and most likely saving my transaxle haha.

 

Both the transmission and rear diff can use 75w90 gear oil, you just want to make sure you use a GL4 rated gear oil for the transmission and a GL5 rated for the rear diff. If it says it is GL4 and GL5 then you can use it in both. I have ran Redline for years and have even used Motul 300 a few times.

Just makes sure you use the right stuff for the conditions you live in. Redline MT90 is better suited for warm/hot conditions, while their MTL is better for really cold conditions.

 

I picked up the oil today and went with Amsoil 75w90 and 75w90 Severe Gear for the diff. I figured the diff should be alright as I live in the mid part of Alberta Canada. I also picked up some 5w40 "European Car Formula" for when the oil gets changed next. Preferred customer for the win!

 

You cars specification is : Gear oil: SAE 75 W 90 (synthetic oil)
Part Number: G 005 000 (1 Liter). Your capacity is 1.9 liters.
So of that part number get to bottles. When you fill the diff just put all of it in then let the excess run off, when it evens out tighten up the plug.