shakey Posted November 16, 2011 Posted November 16, 2011 on my final build and need to add the oil. ive got a type nine box with the tranx straight cut internals, and a sierra 3.92 ltd slippy diff,, any tell me the best oil for them please, Quote
robo1968 Posted November 16, 2011 Posted November 16, 2011 Mine also has type 9 box straight cut and uses Fuchs Pro 4 15W/50 oil (as does my engine). My Quaife LSD diff uses Fuchs Boa 90LS. Hope this helps. Quote
Blatman Posted November 16, 2011 Posted November 16, 2011 For a type 9, use a 75/90 synthetic or a straight EP90. But whichever viscosity, use a GL4 spec oil. Using GL5 in a type 9 can lead to synchro damage. DO NOT use ATF in a type 9. For the diff, use the same viscosity as above but to GL5 spec. If the Sierra diff is a standard viscous type then you DO NOT need any special oils. Same is true for ATB equipped diffs. If it's a plate diff then you DO need special LSD oil. The GL rating will be on the label on the back of the bottle... Quote
robo1968 Posted November 17, 2011 Posted November 17, 2011 Question for Blatman:- I was quoting the oils I use (Fuchs Pro 4 15W/50 for gearbox and Fuchs Boa 90LS for diff) only because that's what my car's builder told me he used. Do you think they are good choices? Quote
Blatman Posted November 17, 2011 Posted November 17, 2011 Dunno... I do know that, to the best of my knowledge most transmission oils used in the UK are somewhere between 75 and 90 for viscosity. I have no idea if engine oil works in a gearbox but becuase it's thin(ner when hot), in theory you'll get more power to the wheels compared with thick(er) transmission oil. Whether that "extra" power is noticable or not is debatable. I suspect it's measurable on a dyno, but through the seat of yer pants? Probably not. I also have no idea what friction modifiers are in engine oil and if they are compatible with whatever synchros you have in the 'box. Does your 'box have brass or steel synchros? Intuitively, engine oil should be in the engine, and gearbox oil in the gearbox. If we didn't need both, they'd surely not produce both, would they? Furthermore, I suspect if you aksed an oil supplier for gearbox oil he probably won't give you a gallon of engine oil... As for do I think using engine oil in the 'box is a good choice... Personally, I wouldn't... BUT, I'm not an oil or gearbox specialist... Quote
Rory's Dad Posted November 17, 2011 Posted November 17, 2011 Now that you're not allowed to warm up the gearbox and diff in the paddock by jacking it up and giving it some revs, I believe engine oil is used instead (or so a green and mean little bird told me). It's not like they do many miles... Rory's Dad Quote
bobsy Posted November 18, 2011 Posted November 18, 2011 I know little about this, and truthfully would as the opinion on the forum if it were mine. But when we done 4x4 I heard some people used automatic transmission fluid in the gearbox. It was I believe done to get a bit longer out the box once it got a bit crunchy. I personally have never done it, but asked the question on here a while back to guage opinions. Then a couple of months back, when they promised snow, I sold it as it was, so have no idea if it works. Quote
robo1968 Posted November 18, 2011 Posted November 18, 2011 Does your 'box have brass or steel synchros? I'm not sure if it has steel or brass synchros, I don't really know what to look for but I do have some pics (from the build) which show the gearbox - it looks like there's something a bit brass coloured in there? What difference would that make - steel v brass? and would that make a difference to the gearbox oil type? Quote
Blatman Posted November 19, 2011 Posted November 19, 2011 Steel synchros need to be checked every so often. They are tougher but less "slippery" than their brass equivalents. Not sure if that makes a difference to the oil used but with steel synchros the 'box should be removed and inspected periodically, which means the oil gets changed more frequently. Gearbox warming for sprints notwithstanding (and why jack it up and rev it? Just leave it in first ticking over for a few minutes. It doesn't have to be *hot*, just not cold... IMHO... ), oils are more than just the sum of their parts. Gearbox/transmission oils are labelled EP. EP = Extreme Pressure. If engine oils can't deal with the same pressure the risk is all the oil gets squeezed out of a part by the pressure and you could have metal to metal contact. But when we done 4x4 I heard some people used automatic transmission fluid in the gearbox. It was I believe done to get a bit longer out the box once it got a bit crunchy. Common problem with Ford boxes. MT75's which the later 2.9 and 2.0l XR4x4's used do indeed use MT75 gearboxes and ATF is the oil to use. Westfields use MT75's as well as Type 9's but the correct oil is often confused because of the rather simplistic view that a Ford 'box is a Ford 'box. This is NOT the case. ATF is a GL5 spec oil. Type 9's require GL4 spec. GL5 spec is "slipperier" than GL4, but that is NOT necesarilly better. The slipperier GL5 in a type 9 may cause the synchros to fail to "bite" when changing gear, leading to crunchy changes and ultimately damage to the synchros themselves, especially if the 'box is being used "enthusiastically"... Quote
robo1968 Posted November 19, 2011 Posted November 19, 2011 Ok so I had a chat with the builder on the reasoning behind using Fuchs Pro R 15w 50 in the gearbox. Synchros are brass and Pro R is a fully synthetic ester based oil with zinc additives. Standard gearbox oil uses EP additives, but too higher EP levels will affect the operating performance of brass syncro rings as the additives will ‘plate’ to the brass surfaces. The use of Pro R in the gearbox was the advice from the techy guys at Fuchs. Pro R 15w 50 is also recommended in motorcycle gearboxes. http://www.opieoils.co.uk/p-68899....il.aspx Quote
Blatman Posted November 19, 2011 Posted November 19, 2011 EP additives are ester based, some with, some without Zinc. Synthetis engine oils are ester based... http://en.wikipedia.org/wiki/Extreme_pressure_additive Some cars are specced to use engine oil in their boxes, like some of the Honda derived Rovers and some actual Honda models. Fords are supposed to use ATF GL5 in the MT75 or EP75/90, EP80 or EP90 to GL4 spec in the type 9. YMMV, but I tend to use what the manufacturer specs as they will have spent *millions* during developement on this sort of thing. Quote
Blatman Posted November 26, 2011 Posted November 26, 2011 And now that I've spoken to an engineer of my acquaintance... Put engine oil in the gearbox if you want. Change it often. Put gearbox oil in the gearbox and you'll pretty much never have to change it. Engine oil can be used becuase it is thinner and heats up more quickly. This is good for track / race cars. It is NOT good for road cars. Engine oil in the gearbox of a road car is NOT reccommended by my engineer. Engine oil in a track car is reccommended as long as you change it every few thousand miles, if not sooner. Quote
robo1968 Posted November 26, 2011 Posted November 26, 2011 Do you think an oil that is rated both GL4 & GL5 would be suitable like this:- Oil for a type 9 (with quaife internals)? Quote
Blatman Posted November 26, 2011 Posted November 26, 2011 No idea. The specs look right, but I don't understand the differences bewteen GL4 and GL5 enough to know if they can be safely combined in to a single product. But there are enough GL4 products out there. I use Red Line MTL in my straight cut, brass synchro type 9 track car 'box... Quote
robo1968 Posted November 26, 2011 Posted November 26, 2011 Ok thanks, Red Line MTL that's helpful and will probably try that. Quote
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