From what I can ascertain, the M56 transmission calls for a GL-4 gear oil. In a nutshell, GL-4 has less additives in it than GL-5. Additives are good and all, unless you have brass and other metals in your transmission (i.e., snychros?), these metals are actually fudged up by the sorts of additives found in GL-5 gear oils. Hence necessitating a pure GL-4 gear oil...
Manual transmission fluid: Volvo synthetic gearbox oil 1161423
Capacity: 2.2 US qts (2.1 liters)
Naturally, most will say to use the dealer/OEM gear oil.
Fully synthetic. API-GL4. At approximately $20 a liter (from one of our favorite online Volvo parts retailers), it's actually not too pricey considering the alternatives.
But here are some other alternatives:
Pentosin MTF-2 (75W-80)
Fully synthetic. Seems a little pricey over at Amazon ($27.95 a liter!).
That being said, I have yet to read anything negative about any of Pentosin's products. Seems like a great way to go, if you, you know, have that kind of bread to spend!Redline MTL (75W-80)
Fully synthetic. Redline seems to have a following and, of course, has its naysayers. From what I can tell, it seems like a good alternative to the Volvo brand gear oil. It's really not that much cheaper than the Volvo stuff... Which makes me wonder, do folks tend to choose Redline MTL because of price or because of some other factor? (For example, does it perform better in cold winters than the Volvo branded stuff?)
Motul Gear 300 LS (75W-90)
Fully synthetic. There are many who swear by Motul Gear 300LS. It's got great reviews on Amazon and on the web. Like Pentosin, Motul is known for their quality fluids. But at $21 a liter on Amazon, this is coming across pricier than the Volvo branded stuff!
Sta-Lube MultiPurpose Hypoid Gear Oil (85W-90)
Not synthetic. Old fashioned, 80s packaging! Reminds me of the kind of "no frills" packaging that used to be found on certain store brands back in the day. Has anyone heard of this? I just spent the better part of an hour reading forums on folks who use this. A lot of old gearheads who are crazy enough to maintain VW busses run this in their transmissions and swear by it! It seems to be available at any NAPA and at $27 a gallon, it's probably the most cost-effective 85W-90, Gl-4 gear oil around. Anyone have any luck putting this into their transmissions? I am imagining that this oil is for someone who might want to drain their gear oils more often than usual?
Pennzoil Synthetic Gear Lubricant (75W-90)
Fully synthetic. GL-4. And from Pennzoil. Some folks love their Pennzoil. One would think that you could find this in an Autozone (they sell all their other Pennzoil stuff...) but no, you won't find this everywhere. In fact, half of the reviews on Amazon complain about how hard it is to find this oil. (The other half complain about the tip that needs to be cut in order to be poured?) No one seems to be complaining about the price. At over $30 a quart, this stuff is super expensive... Anyone put this into their tranmissions?
Ford Fluid XT-4-QGL Gear Oil (75W-90)
I don't think it's synthetic... It's Ford. I know they make decent oil filters. (Nothing any of us would ever use... but decent for other cars!) I might put this into my car. Again, if it didn't cost more than the Volvo branded stuff. At $24 a quart (a quart!!) you have to really believe in this to use it. Anyone try this?
Brad Penn Penn Grade 1 Multi-Purpose Classic (80W90)
Dyno oil. Love the "classic" on the bottle! Isn't my wife's 98 a classic? It's a GL-4 and one review on Amazon has someone using in their 56 something or another... I guess it would work. It's only $10 a quart.
Anyone experiment with this?Comma EP80W-90 GL-4 Mineral
Unsure it if it Dyno or Synthetic. Absolutely love the little British flag in the lower left hand corner. It is EXTREME PRESSURE GEARBOX OIL. (Are our M56s extreme pressure?) It is super expensive over at Amazon, $18 plus $20 shipping...
Royal Purple Max Gear High Performance Synthetic Automotive Gear Oil (75W-90)
Fully synthetic. OK, here we start to delve into those GL-5/Gl-4 gear oils... The best of both worlds? Not sure. It's got a hella lot of good reviews on Amazon. From what I've read, synchronizer safe should mean it's good for the M56... What are the experiences using this gear oil? It's about two bucks cheaper than the VOLVO OEM stuff.
They write:
Max Gear is recommended for use in truck and automotive front or rear differentials, manual transmissions and lower gear units of marine engines that specify use of an API GL-5 or GL-4 fluid. It is non-corrosive to soft yellow metals (brass, bronze, copper, etc.) and synchronizer safe. Specially designed to extend gear and bearing life, Max Gear provides superior corrosion protection over competing conventional and synthetic gear oils.
It sure sounds like it does it all! Maybe it can fix my P0455 code!
LiquiMoly HYPOID-GETRIEBEOL (75W-90)
Like Pentosin (and to a lesser extent, Motul) here's LiquiMoly's HYPOID-GETRIEBEOL! It is fully synthetic and seems to be compatible with everything out there. It's another one of the GL-4/Gl-5 gear oils out there. It's $17 bucks with prime shipping. I almost pulled the trigger on this one. Seriously, what is there not to trust about LiquiMoly? But it's only got one review. (And it's a crappy review about better gas mileage! Who cares about mileage, I want buttery shifting!) Could any of you see yourselves using this? It certainly sounds like it'll work... And work kind of nicely. Hmmmm
Here's what they write about this oil:
Liqui Moly's Hypoid Gear Oil TDL SAE 75W-90 (GL4/GL5) is a multi-purpose gear oil for universal application in commercial vehicles. This "TOTAL DRIVE LINE" (TDL) gear oil is most suitable for lubricating all drive elements, from synchronized and non-synchronized manual transmissions to geared axle drives. Because of the reduction in the number of product types and the reduced risk of confusion between them, Hypoid Gear Oil TDL contributes significantly to streamlining the modern vehicle fleet. Reduced friction as a result of the optimum viscosity level helps to save fuel. Universal use for all manual, auxiliary and differential transmissions. The transmission manufacturer's instructions must be followed. <-- LOLZ
LiquiMoly HOCHLEISTUNGS GETRIEBEOL (75W-90)
Fully synthetic. Gl-4+ (GL-4/GL-5). (Does anyone know what that + means?) OK, I just went through the slow LiquiMoly website, plugged in my car, and it's telling me that this is not the gearbox oil for me... CRAP!
Here's what they write about their gear oil:
Liqui Moly's Hypoid Gear Oil SAE 75W-90 is a fully synthetic, top grade, high-pressure gear oil for high load manual, auxiliary, transaxle and hypoid transmissions, where a lubricant complying with API GL 4+ is required. High quality synthetic based oil and modern additive technology ensures a broad application range and optimum transmission lubrication under extreme conditions. The low viscosity characteristics of this gear oil make it also suitable where shifting difficulties exist. (eg. stiffness or noise generation). Promotes easier gear changing and quieter running. With outstanding protection against wear and corrosion. Guarantees a considerable reduction in noise. Suitable for use where there are long periods between oil changes. For passenger vehicle manual transmissions, modern transaxles drives. Predominantly in VW transmissions and those of numerous other vehicle manufacturers.
LiquiMoly GETRIEBEOL (75W-80)
LiquiMoly's pure GL-4 gear oil. I don't know if it is synthetic. Can't seem to find the information... $19 a liter is pretty pricey...
OK, LiquiMoly's website says that this is the oil for our cars:
LiquiMoly HOCHLEISTUNGS GETRIEBEOL (75w-80)
It's fully synthetic, exactly the specifications from Volvo (GL-4, 75W-80), in fact, it's so accommodating, it'll do GL-3! However, it is not available in the US. You can get it online, but it's kind of expensive (approximately 11 Euro) and comes in half liter bottles!
They write:
Getriebeöl auf Basis Synthese Technologie mit extrem hoher Leistungsreserve. Sorgt für ein exaktes Reibverhalten und bietet eine hervorragende Alterungsbeständigkeit. Übertrifft die hohen Testanforderungen namhafter Fahrzeughersteller. Gewährleistet selbst bei langen Ölwechselintervallen die maximale Performance. Mit modernster Verschleißschutztechnologie. Ermöglicht leichteres Schalten.
I'm sure it says here why they have a HOCHLEISTUNGS GETRIEBEOL in GL-3+ AND one in GL-4/Gl-5...
EDIT:
Then there's the Mobil 1 5W30 (thanks for the reminder renns!)
I forgot about this one! Yes, it's been reported in quite a few threads about the use of Mobil 1 in our transmissions. This seems like the most economical way to get a good oil in there... And it's readily available! (I'm thinking this might be a good oil (the 0.1L) to add to the Volvo OEM? Especially since it would seem like a waste to purchase 3L just for that 0.1L)
There's also this Gear oil available at Pelican Parts for a pretty great price...
FUCHS Titan Sintofluid 75W GL-4
Don't know anything about this one... Looks like a really great option for the price.
OK, everyone... What do you all think? What have you used? What will make my transmission melt? What will keep it going until I reach 300,000 miles? Is all of this really moot? Have I spent the last five hours researching all for naught? I read somewhere you can stick regular oil in here? Does that mean I can put some Mobil 1 Synthetic High Mileage in here?
Thanks for your response everyone!- Marco
