Gearbox Oil Additive

[Waddles]

Gidday Darren,I have been advised to get a good quality oil that meets the API GL4 spec. When searching for a suitable oil, the only one available with that spec was Nulon SAE 80 Smooth Shift Manual Gearbox and Transaxle oil. Full mineral.Now, the salesman, who appeared to have some knowledge on the subject said that the GL4 spec had been superceded by the GL5 spec. In other words, the GL5 oil has all the properties of the GL4 plus some more. He even called the GL4 stuff "tractor oil".With your experience in the industry, I"d be interested in your opinion on this one please.Waddles.

[yoshi]

Hi AllWaddles, the salesman you spoke to is partly correct in regard to the GL4 + GL5 comparison. GL5 does superceed the GL4 in many respects, the greatest differance however is in the amount of EP (extreme pressure additive) present in these oils. A rule of thumb in the industry is that GL4 oils have approximately 50% of the EP additives found in GL5 products, this in turn may or may not be beneficial depending on the application and use. EP additives are generally comprised of phosphorous sulphur compounds, these compounds have a tendancy to be reactive with yellow metals (copper, bronze etc). If you wre to use a GL 5 oil in say an old Holden gearbox fitted with synchro rings the EP additive in some GL5 oils would actually attack the synchro"s and over time eat them awayThere are many oils from a variety of manufacturers that meet the GL4 spec, it comes down to whether you want to use either mineral or synthetics, I am sure you could use a GL5 in the Autoflight boxes as they probably don"t contain any yellow metal (however I stand to be corrected on that) What is the OEM reccomendation in regard to SAE grade for use in the Autoflight box?CheersDarren

[tonydenton]

waddles , do you have heil h. e-mail address available please?

[aussie_paul]

waddles , do you have heil h. e-mail address available please?info@autoflight.co.nz

[Waddles]

Yoshi,When I bought my box in 04, the recommended oil was Syntrax Manual 75W90. At the time it was a semi synthetic. The latest though is full synthetic. Not sure of the pros & cons of mineral vs semi synthetic vs full synthetic and can"t find good specs. After 25 hours though, the honey coloured syntrax that went into the box came out almost black. diffiocult to spot metal particles without a magnet. I am aware that after 300 hours of operation, a lot of that circuit training, the box will have suffered some normal wear and tear, so maybe that"s all it is???I went to Wikipedia and under Gear Oils found some useful information including comparisons between the oils with differing GL specs and a discussion on different uses for the different oils. Useful background info.I changed my oil today and will fly on Saturday and report the findings back here.Tony. I see Paul has posted the email address you wanted.Waddles.

[tonydenton]

ok thanks to both.

[Brian]

Hi AllChopper - All I was trying to say is there are a lot of things to consider when selecting an oil, and gave an example of how increases in temperature have a negative effect on oil useful life. I stand by my statement of you usually get what you pay for, and we would all be surprised if we actually new what we were paying for when buying aftermarket oil additives. I"m certainly not saying there aren"t some good additives on the market today, but if you buy good quality oil, these additives and others are already present in varying forms. My opinions are based on 20 plus years in the mechanical field and another 5 years as a diagnostic technician for one of the countries largest independent oil testing laboratories and the past year as a technical advisor for an oil manufacturer, I"ve seen litteraly hundreds of thousands of working oil samples and seen the results in the real world. I have also seen lots of people ripped of by aftermarket additive distributors making all sorts of promises.Like I said these are just my opinions, nothing more and nothing less.Safe flying to all.DarrenI wasnt having a go at you Darren, merely stating that it seems science doesnt always gets it right. I agree, usually the quality product is more expensive.While talking the pros & cons of synthetic, years ago I tried Mobil 1 fully synthetic I think, expensive but it went black [really black] after 50 hours where as the semi synthetic I was using was no where as dirty after 50 hours

[Waddles]

Flew yesterday for a couple of hours with an OAT of 38*, official. I suspect a bit warmer over the runways.Temps went up to the red lines fairly quickly, but returned to normal equally quickly once established in cruise. A series of climbs and descents produced similar results. The gearbox oil temp definitely cools a lot quicker now.I"ll run the straight oil for the next 15 hours, then change it adding a stabiliser for another 25 hours.Over all, I feel there is an improvement.Waddles.

[Russell]

Al, ol son..............me and her ;D, gave me ol machine a right workout today, was trying to see just how high me temps would go, then return to "norms"Ok.......FULLY loaded, air temp around 32, altitude 2450 at ground........full power climb out, held at 55.....60kts, i just let her go and go for about 5 mins.....water temp never exceeded 85, gearbox similar. Reduced power to cruise, temps immediately dropped to around 81 approx, and there they stayed. Dropped to around 400ft AGL and again opened her up, this time reduced rate of climb to around 200FPM, speed was around 80kts plus, held this for several minutes, again temps were similar as above ( tad lower perhaps )My gearbox oil is that new syntrax stuff, just renewed actually ( drained/refilled )Ol mate this way says temp probs just whack on a small/compact oil cooler.....easy as, in fact he reckons all our machines should have one fitted. ( Rotax have a little beauty )Off topic...........keen to get a set of them blades made your way, compare with what i got...........might be better, might be no better.....keen to see.

[Waddles]

Thanks Russ,Reckon I could improve the engine temps by fitting my old radiator, but that is not my biggest concern. Problem with an oil cooler for the gearbox as I see it, is that a pump would also be needed for circulation of the oil and I haven"t researched that yet. Any suggestions from the gallery please.Blades to suit our machines are not ready yet. Nick is busy at work.Waddles.

[Russell]

sorry folks......i could have been more clearer.........oil cooler, yea engine oil cooler i meant.

[tonydenton]

al, don"t dismiss modern tractors and tractor oil or any tractor/implement as being inferior, the technoligy that has been in tractor gearboxes especially and also the diff and not forgetting the high tech hydraulical systems [ all the one oil resevoir] is surpassed by nothing else with an engine bolted on the front of it.[ in my opinion]

[Waddles]

Thanks Tony,I"d prefer an electric pump for ease of installation, but have yet to research that side of things. I have a small radiator that used to be the heater core on the original RAF. Thought that might do the job. I"ll look about some more when time permits.Regards,Waddles.

[yoshi]

Hi AllWaddles -

[aussie_paul]

Thanks Tony,I"d prefer an electric pump for ease of installation, but have yet to research that side of things. I have a small radiator that used to be the heater core on the original RAF. Thought that might do the job. I"ll look about some more when time permits.Regards,Waddles.Allan, I don"t think the RAF water heater core would take the higher oil pressure.Regards, Aussie Paul.