What's the big deal with VAG OEM Castrol gear lube

[dparm]

I swear, after perusing some of the online VW/Audi communities, I'm totally lost as to why they are so excited to use the OEM Castrol gear lubes. I've pulled up the specs of what the fluids really are (VAG rebrands them) and they look rather mundane and generic.


My car, for example, should use this as its MTF/center differential oil:

Castrol TAF-X 75w90
aka "VAG Transmission Oil"
API GL4/5
VI = 210
KV @ 40C = 73.0
KV @ 100C = 14.4
$26.50/liter @ dealer

For the rear differential, it uses:
Castrol SAF-XO/Syntrax Longlife 75w90
aka "VAG Gear Oil"
API GL5
VI = 162
KV @ 40C = 103.7
KV @ 100C = 15.7
$39.21/liter @ dealer ($10/L @ Land Rover)


I'll admit the TAF-X is a decent oil specification wise, but when you have something like Motul Gear 300 that meets or beats it in every area for about $5/L less (and can be readily had in the USA), it's hard for me to understand why anyone runs this other than for warranty reasons.

The SAF-XO is a major yawn-fest, with a mediocre VI and rather thick viscosity at lower temps. When warmed up it's not bad, but again, Gear 300 costs much less and is superior in almost every way. BTW, this fluid is used by a lot of other European marques like BMW (XJ variety which is 75w140 in M3s) and Land Rover.

My car specs GL-4 75w90 for the tranny, and GL-5 75w90 for the rear diff. So almost anything will work. I'm totally satisfied with my Motul.

Anyone care to throw in their $0.02?

 

[ChiTDI]

The guys that do their own work go for Motul or other name brands over Castrol by a large margin.
Engine oil same way.

 

[The_Eric]

I've found that most brand specific forums are hardcore OEM everything users. In many cases, they are good intentioned manual readers who believe EVERYTHING it says and most every manual will say something to the effect of "Use our stuff or your car will blow up"...

 

[dparm]

If anything, I think the German car forums buy into it more than anyone else.

The Honda forums I used to go on were quite the opposite. Everyone knew the OEM stuff was just the basics and there was a whole other world out there.