# RP gear oil?



## hunterkb (Nov 20, 2009)

im about to change the gear oil on my MK4 GLI and i was just wondering if there is anyone thats using the 75w-90 RP gear oil. i know there are a lot of mixed reviews about RP. i just put 5w-30 in my engine and i like it so far i think im going back to mobile 1 after this though. but anyways i was just wondering what your guys thoughts are on the RP gear oil. I almost went with the lucas oil. hopefully i made the right decision.


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## AudiSportA4 (Mar 3, 2002)

Major skip, but not as big a skip as Lucas.

AMSoil did an extensive gear oil test, and as usual Royal Purple and Lucas fell on their face.

http://www.amsoil.com/lit/g2457.pdf

I use Redline, the MTL 75w-85 should serve you well.

On the subject of Lucas, check out this elemental VOA analysis of Lucas "Oil Stabilizer" 

Unless listed all are 'Zero'

Lucas Virgin
TBN - 0.1
Visc - 615.3
FP - 435
Calcium - 3
Magnesium - 1
Phosphorus - 4
Zinc - 2

http://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=890132&page=all

Nothing in it, just a quart of greasy slop for $10


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## skier45 (Jul 27, 2009)

*does anyone else do ok in an amsoil test*

amsoil test=infomercial. consider the sourse


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## harmankardon35 (Sep 16, 2009)

LOL lucas. I once had to tear down my buddies mazda after a bottle of that stuff was added...there was a super thick, sticky blanket covering all the valves and it had begun to sludge up quite badly (probably because it blocked the oil flow at the filter screen) It turned an ok engine that didn't use any oil into a burned out mess. I got it running, but it continued to smoke terribly and lost a lot of power. Theres a lot of bad info from credible sources when it comes to lucas, and i agree royal purple isn't that much better.


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## rhouse181 (Apr 13, 2008)

I've had good experience with RP syncromax in a Getrag transmission with some mileage on it. Really smoothed out the shifts and helped the 1st to 2nd shifts when cold. Was not impressed with Amsoil 75w90 in the same transmission, made it nearly impossible to use... But that comparison is apples to oranges because of the viscosity difference between the two...

When I drain the box on my GTI, i'll probably fill it with Red Line 70w80... seems to be a good compromise in viscosity and i've been pretty impressed with their lubricants in general


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## AudiSportA4 (Mar 3, 2002)

AMSoil makes top-flite products, regardless of what their MLM marketing does. I trust their R&D implicitly. However bad their marketing is, it has more merit than adding purple dye to an mediocre oil and then not even publishing basic data on it. 

Royal Purple is the pretty-boy's LUCAS, both fool's gold.


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## AudiSportA4 (Mar 3, 2002)

rhouse181 said:


> I've had good experience with RP syncromax in a Getrag transmission with some mileage on it. Really smoothed out the shifts and helped the 1st to 2nd shifts when cold. Was not impressed with Amsoil 75w90 in the same transmission, made it nearly impossible to use... But that comparison is apples to oranges because of the viscosity difference between the two...
> 
> When I drain the box on my GTI, i'll probably fill it with Red Line 70w80... seems to be a good compromise in viscosity and i've been pretty impressed with their lubricants in general



Def a big difference in visc there. I used RP before and it was fine. My understanding is that the additives don't last very long and shift quality degrades rapidly. That's what I'm told. I have no problem relying on AMSoil's white paper for the data. I don't see why someone would criticize a comparative bench test, seems a lot better than the dreck most oil companies put out.

I change gear oils very infrequently, so it's not a huge matter for me, but recently I use RL exclusively, a speed shop 2 blocks away has it in stock.


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## AudiSportA4 (Mar 3, 2002)

A representative from LUCAS would now like to make a statement...


"IT'S GOOD!!!"

http://i15.photobucket.com/albums/a364/AudiJunkie/*******.jpg


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## skier45 (Jul 27, 2009)

*aka audijunk*

You look as I expected you might. I didn't think you were that tall though.


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## hunterkb (Nov 20, 2009)

thats a lot guys that link helped a lot. im gonna try and get rid of the RP and get some AMS:thumbup:


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## AudiSportA4 (Mar 3, 2002)

Remember, 75w-90 is very thick. Some of the newer oem MTFs are 7 to 8 cSt like ATF, not the 15 cSt of old. 10 to 12 cSt is a good medium. Syncromesh products are more like 8 to 9 cSt and would be the best in cold and the best mpg. Redline MTL 70w-80 and 75w-85 are 10 and 12 respectively., AMSoil has a similar product too. 

Another thing, I see you mentioned Mobil 1 "Gear Oil". It is indeed GL-5 gear oil, not GL-4 manual trans fluid and therefore has excessive friction modifiers that keep the syncros from engaging quickly. Don't use that stuff. M1 is a fine gear oil for diffs and such.


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