# Gear Oil Advice OA4 VW Transmission (2.5L Rabbit)



## Servo888 (Feb 25, 2007)

Hey all,
I need some suggestions on gear oil. From my research, I need 75W90 GL4 Synthetic. I've heard recommendations for Royal Purple, Redline, and GM Syncromesh, but all three have had sketchy long term reviews. Some folks claim Redline causes excessive wear, Royal Purple damages yellow metals (even though it says it doesn't), and GM Syncromesh is only good for 10k-20k miles until it needs to be replaced, since it's not synthetic.


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## tungub (Apr 7, 2007)

*Re: Gear Oil Advice OA4 VW Transmission (Servo888)*


_Quote, originally posted by *Servo888* »_Some folks claim Redline causes excessive wear

Who says this? I've never heard it. And I've run Red Line in almost every vehicle I've ever had, including my GLI, and never had an issue. O say put in RL MT90 or MTL and enjoy the smooth shifting.
robert


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## Servo888 (Feb 25, 2007)

*Re: Gear Oil Advice OA4 VW Transmission (tungub)*


_Quote, originally posted by *tungub* »_
Who says this? I've never heard it. And I've run Red Line in almost every vehicle I've ever had, including my GLI, and never had an issue. O say put in RL MT90 or MTL and enjoy the smooth shifting.
robert

Here's what one guy on carreview.com wrote

_Quote, originally posted by *kparris* »_
I strongly advise against usiung RedLine oil for use in transmissions, period. In my experience it offered no real benefit (in drivability or otherwise) over the OEM oil., and may even have caused damage. I used 75w90ns gear oil in my 01 Prizm since it was new and the transmission just failed (complete lock up) at 87k miles. One of the countershaft bearings went out. This is an extremely rare failure for this Toyota transmission. In fact, I could find no other instance of this type of failure. I therefore conclude it was due to the RedLine oil.
...
As to synchro wear: the synchros in my transmission wear good as new, as were the gears, but the bearings went out.



And another one from thesamba.com

_Quote, originally posted by *tungub* »_
I've rebuilt two Syncro trannies in the past two years that were subjected to above-average strain, both had been on Redline MT90 since their previous rebuild. Tranny # 1 was from my personal Syncro Westy, big tires, TDI 'pumped up' and used for lots of off-road and some towing. The main failures were in the low gear needle bearings and mainshaft bearing next to 4th gear. The mainshaft was toast as was low gear and the pinion shaft.











Maybe I should just buy some VW oil.


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## mjmi11er (Apr 8, 2002)

*Re: Gear Oil Advice OA4 VW Transmission (Servo888)*

don't want to hijack the thread but i have a similar question for the 02J.
i have been looking at the same oils you have brought to the table.
but there is another option. vw gear oil, and just doing a replacement of the stock stuff.
why not? there would be no ill effects from it. do you really gain anything by going aftermarket here?


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## mjmi11er (Apr 8, 2002)

*Re: Gear Oil Advice OA4 VW Transmission (mjmi11er)*

anyone? should the oem gear oil be considered or is the aftermarket stuff that much better?


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## mjmi11er (Apr 8, 2002)

*Re: Gear Oil Advice OA4 VW Transmission (Servo888)*

anyone?


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## herb2k (Jul 29, 2007)

I'd say if you're concerned then just get the OEM stuff from your dealer...


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