longevity of mobil 1 75w90 gear oil?

[staubach333]

about this time last year i drained my original trans and diff fluid in favor for mobil 1...the original factory fluid had about 100k on it and still looked ok...this mobil 1 has about 30k on it now...my question is how many miles will the mobil 1 last for?

[B6JoeS4]

well over 100k. most people never change their tranny oil.

[V A4 Life]

Your stock trans oil was GL4 and Moblie 1 is GL5. GL5 is bad for your trans and you should drain it ASAP. EP in Moblie is eating the brass synco's and bearings in your trans. Really change it now, Redline MTL is great for cold but anything that is rated GL4 only is better that the Moblie you have in there. I KNOW IT MAY SAY BOTH. GL4 only 75W-90 is what you need. Good Luck

[blmlozz]

Your stock trans oil was GL4 and Moblie 1 is GL5. GL5 is bad for your trans and you should drain it ASAP. EP in Moblie is eating the brass synco's and bearings in your trans. Really change it now, Redline MTL is great for cold but anything that is rated GL4 only is better that the Moblie you have in there. I KNOW IT MAY SAY BOTH. GL4 only 75W-90 is what you need. Good Luck

need some confirmation of this.. not only because it's serious, but because that opens up opportunity for lawsuits if it disentigrates components and the bottle says GL-4 compliant. My 01-a is running strong after tens of thopusands of miles on the 75-90w ls mobile 1


also, because I have mobil 1 in my o1-e.

[slayerrule]

yes mobil1 is gl5 and thats what its says on the bottle you should definitely drain it and fill it with some redline mtl

Mobil 1 Synthetic Gear Lubricant LS 75W-90 meets the most severe API Service MT-1 and GL-5 EP gear oil service classification.

taken from http://www.mobil.com/USA-English/Lub..._LS_75W-90.asp

[blmlozz]

what about the rear diff? is GL-5 okay there?

[Squarrl]

GL-5 is fine for the rear diff since it has no syncros. GL-5 eats brass which is what your syncros are made from. GL-4 is brass safe.

[Jeff]

Redline MT-90 or OEM. There are other oils claiming to be "GL4 AND GL5 Compatible"... do not use this either in your trans.

In the rear diff, use GL-5 75w90.

[mike-2ptzero]

I run Motul 300 which plenty of Audi/VW shops sell. I haven't had any issues running it and is a GL4/GL5 rating.

Posted on Vortex

An oil that meets the GL-5 specification is basically a GL-4 oil that has been enhanced so it resists shearing forces, like those found in differentials. If an oil meets both the GL-4 and GL-5 specifications, as does the Motul oil you're asking about, you may use it in both transmissions and differentials, so the answer to your question is "yes".

[blmlozz]

I run Motul 300 which plenty of Audi/VW shops sell. I haven't had any issues running it and is a GL4/GL5 rating.

Posted on Vortex

i ran it in my 01a for at least 40K and I don't have any problems, only had it in the 01e for about 10-15k but it's still shifts okay.

[Jeff]

I run Motul 300 which plenty of Audi/VW shops sell. I haven't had any issues running it and is a GL4/GL5 rating.

Posted on Vortex

I've ran the Gear 300 Motul before, and it also worked great. But the MT-90 gave me better synchronization when pounding through the gears and smoother shifts (when warm), I would get slight grinding on the Motul. But I am also running a 01E Getrag gearbox.

GL5 fluids typically have a much higher sulfur content, and that sulfur is what eats up brass synchros. So I don't know what companies like Motul did to make their GL5 also GL4 compatible without altering the sulfur content. For me, I just put in a fluid that I know is 100% GL4 that's also been proven to work (not to mention more readily available and a bit cheaper compared to the Motul).

[staubach333]

wow i didnt know that...the trans couldnt shift smoother...so should i really swap it out? it is used to the gl-5 stuff im afraid if i swap it back to gl-4 i might run into problems

[Jeff]

wow i didnt know that...the trans couldnt shift smoother...so should i really swap it out? it is used to the gl-5 stuff im afraid if i swap it back to gl-4 i might run into problems

You won't have any synchros left by the time you waited. I would switch it to GL4. The GL5 has a much lower coefficient of friction (more slippery), and in most cases, allow your synchros to "appear" much smoother (because they aren't even working), only to fail in time. Switching back to GL4 will not give you problems (only happens with ATF in automatic gearboxes when you switch fluid types).

Make sure the fluid is GL4 only, in a 75w90 weight. The only other "GL4 AND GL5 compatible" fluid I would maybe use (if I had nothing else) is the Motul Gear 300.

[staubach333]

i put about 30k miles on the trans with this gl-5 fluid, do you think the synchros wore at all in that timeframe?

[blmlozz]

i put about 30k miles on the trans with this gl-5 fluid, do you think the synchros wore at all in that timeframe?

30K on gl4 is enough for moderate wear.. so add gl-5 and i'm sure they're fairly worn for only 30K of work

[mightyb28]

Your stock trans oil was GL4 and Moblie 1 is GL5. GL5 is bad for your trans and you should drain it ASAP. EP in Moblie is eating the brass synco's and bearings in your trans. Really change it now, Redline MTL is great for cold but anything that is rated GL4 only is better that the Moblie you have in there. I KNOW IT MAY SAY BOTH. GL4 only 75W-90 is what you need. Good Luck

http://www.lubrizol.com/DrivelineAdd...arOil/GL5.html

# API Category GL-4 designates the type of service characteristic of spiral-bevel and hypoid gears in automotive axles operated under moderate speeds and loads. These oils may be used in selected manual transmission and transaxle applications.
# API Category GL-5 designates the type of service characteristic of gears, particularly hypoids in automotive axles under high-speed and/or low-speed, high-torque conditions. Lubricants qualified under U.S. Military specification MIL-L-2105D (formerly MIL-L-2015C), MIL-PRF-2105E and SAE J2360 satisfy the requirements of the API GL-5 service designation.

[blmlozz]

Your argument is invalid since he's suggesting the poorer quality gl-4 is better(not from a performance stand point) since the gl-5 eats the brass syncros found in audi transmissions.

[onemoremile]

I called Royal Purple and asked this question and they said the GL4/GL5 synthetic is fine with brass synchros. I asked if he was sure enough of his answer to buy me a new trans in a couple years and he said they haven't had a problem yet. I'll be putting it in my trans in a week or two.

[onemoremile]

FWIW, the 01 S4 I had as a company car has over 255k miles on it's stock fluid. That stuff can last damn near forever. The synthetics are even better so don't worry about it unless there is a leak.