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Gear Lube testing Lab Results
I came across this very detailed lab study of Gear Lubes and found this an interesting read:
http://www.synthetic-oil-tech.com/Gear%20Lube%20White%20Paper.pdf Most interesting was how top end gear lubes FAILED corrosion testing. These failed: Mopar Synthetic 75W-90 with Mopar LS additive Royal Purple Max-Gear 75W-90 Lucas 75/90 Synthetic But in the end the best overall results and winner was: AMSOIL Severe Gear 75W-90 Here are the top 5 in order: 1 - AMSOIL Severe Gear 75W-90 2 - Mobil 1 Synthetic 75W-90 3 - GM Synthetic Axle 75W-90 4 - Castrol SYNTEC 75W-90 5 - Red Line Synthetic 75W-90 I started this because I'm getting ready to change the gear lube in my 915 box and was wondering what to put in. I'm leaning toward one of the top 2 above. What do others run and recommend.
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Sal 1984 911 Carrera Cab M491 (Factory Wide Body) 1975 911S Targa (SOLD) 1964 356SC (SOLD) 1987 Ford Mustang LX 5.0 Convertible |
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Join Date: Jul 2003
Posts: 1,638
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Swepco for 915 transmissions
Mobil 1 for G50 Transmissions |
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Slumlord
Join Date: May 2001
Location: Canada
Posts: 4,983
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1. I would not recommend synthetic in your 915. I doubt the synchro's will feel right swimming in that. But if you are set on doing it please post your results.
2,. I suggest Castrol or Swepco. Non-synthetic. (Wear and corrosion ratings are way down the list or important properties when selecting a 915 oil.) 3. Do you consider that report an independent source of information? Shockingly, the Amsoil Drivetrain Division ranked Amsoil as the best oil.
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84 Cab - sold! 89 Cab - not quite done 90C4 - winter beater Last edited by Porsche_monkey; 09-15-2008 at 12:28 PM.. |
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Bill is Dead.
Join Date: Jul 2005
Location: Alaska.
Posts: 9,633
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It looks like that report deals with oil as used in a differential gear. Although the 915 does have a ring and pinion in it, it also has synchros, brake bands, etc. There is a lot more to consider than just the R&P wear. This is why people recommend against the synthetic... they say synthetic is "too slippery" for the brake bands to work right in the synchros.
Well, I've used Amsoil in my 915 since I rebuilt it; almost a year now, with no balky shifting or other problems. I intend to change it out this winter with Swepco, The Miracle Oil (TM), and see if I notice any comparative difference.
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-.-. .- ... .... ..-. .-.. -.-- . .-. The souls of the righteous are in the hand of God, and no torment will ever touch them. |
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Registered
Join Date: Feb 2003
Location: Kailua, Bend, & Tamarack
Posts: 1,618
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I guarantee that an independant test would yield far different results.
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74 911Ebay
Join Date: Aug 2007
Location: Denver, CO
Posts: 1,035
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To the webs defense, on Bobistheoilguy.com I have read great things about Amsoil.
But it is an election year, and I agree... I find it fishy, that Amsoil found that Amsoil is the best. But we are talking about 915 transmissions, so none of that matters. |
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<insert witty title here>
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I think if you put synthetic is a 20+ year old 915 you're going to be lining your garage floor with cardboard pretty soon.
When I rebuilt my 1972 915 I dumped Castrol in there because I knew I'd have to change it after a break-in period (500 miles or so) and swepco is not only expensive, it's hard to get around here. I had swepco in there before and didn't notice a lick of difference in shifting with the Castrol. When I changed it after the break-in period, I just bought another jug of Castrol and it shifts fine. Well, as good as a 35-year-old 915 ever shifts...
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Current: 1987 911 cabrio Past: 1972 911t 3.0, 1986 911, 1983 944, 1999 Boxster |
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Registered
Join Date: Feb 2003
Location: Kailua, Bend, & Tamarack
Posts: 1,618
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Castrol LSX90 is an excellent oil for the 915.
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Registered
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
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Dose haveing a Limited Slip Diff come into play?
Is there an additive needed for and LSD or somthing? |
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Slumlord
Join Date: May 2001
Location: Canada
Posts: 4,983
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That's a source I would trust before Amsoil...
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84 Cab - sold! 89 Cab - not quite done 90C4 - winter beater |
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