EliTR6 Posted May 19, 2008 Report Share Posted May 19, 2008 Hi all, Fitted new spark plugs and leads yesterday. New (2nd hand) seats went in too. Next up is an oil change for the engine, gearbox, etc. It's going to be a long evening... Picked up 2l of Castrol Manual 80W in Halfords. Is this heavy enough? Thanks! Quote Link to post Share on other sites
marvmul Posted May 19, 2008 Report Share Posted May 19, 2008 It's never heavy enough to get a dry box? 80W (80W90?) is ok I suppose. For the differential, the oil needs to be EP, extreme pressure. This can't be used in a gearbox, surely not in an o/d gearbox. It seems that nobody knows when diff oil has to be renewed, perhaps it needs only be topped up. Quote Link to post Share on other sites
Guest ntc Posted May 19, 2008 Report Share Posted May 19, 2008 Drain gearbox then flush refill with Mobile 1 if overdrive fitted Regard's Ntc Quote Link to post Share on other sites
Jersey Royal Posted May 19, 2008 Report Share Posted May 19, 2008 Drain gearbox then flush refill with Mobile 1 if overdrive fittedRegard's Ntc Ntc, Is this the one you mean http://www.mobil.com/USA-English/Lubes/PDS...t_LS_75W-90.asp Seems to me its a GL5, which is a no no from what i believe. Regards Guy Quote Link to post Share on other sites
Guest ntc Posted May 19, 2008 Report Share Posted May 19, 2008 (edited) Ntc, Is this the one you mean http://www.mobil.com/USA-English/Lubes/PDS...t_LS_75W-90.asp Seems to me its a GL5, which is a no no from what i believe. Regards Guy Hello Guy No believe it or not Mobil 1 engine oil I will see what response this bring's and then explain Edited May 19, 2008 by ntc Quote Link to post Share on other sites
Alec Pringle Posted May 20, 2008 Report Share Posted May 20, 2008 Hi Guy, I reckon that ntc probably has a very valid viewpoint on this one, and I'm looking forward to his explanation with considerable interest. It's always good to learn new stuff ! Cheers, Alec Quote Link to post Share on other sites
Andy Moltu Posted May 20, 2008 Report Share Posted May 20, 2008 nts - are you suggesting Mobil 1 engine oil or mobil 1 gear oil? Quote Link to post Share on other sites
chrismitchell Posted May 20, 2008 Report Share Posted May 20, 2008 I've been following this debate for years. Seems its a design fault. The gearbox should really have a traditional gooey transmission oil, but the overdrive should have something more like an engine oil. But they share the same oil so you can't win. Have been running engine oil for a few years. For short runs its nice and the overdrive is always very slick. But after a long high-speed run (say a few hours of autoroute) the gearbox is quite clunky and notchy, feels like the oil is too thin. Quote Link to post Share on other sites
jerrytr5 Posted May 20, 2008 Report Share Posted May 20, 2008 For the differential, the oil needs to be EP, extreme pressure. This can't be used in a gearbox, surely not in an o/d gearbox.It seems that nobody knows when diff oil has to be renewed, perhaps it needs only be topped up. Just to correct this: Triumph specified EP oils in gearbox and diff with or without overdrive. If you have fitted a diff drain plug, renew the oil whenever you do the gearbox, otherwise you are restricted to topping up only. Jerry Quote Link to post Share on other sites
Rob Salisbury Posted May 20, 2008 Report Share Posted May 20, 2008 Drain gearbox then flush refill with Mobile 1 if overdrive fittedRegard's Ntc Hmm, I expect everything will work quite nicely to begin with, but syncro cups and O/D clutches require friction to work, the Mobile 1 will be just too darn slippery after a while.... think about it, in an engine you want all the parts to slide quietly past one another, in the box and O/D some things have to grip one another.........still I'm very interested to hear the explanation you have Ntc. Cheers Rob Quote Link to post Share on other sites
Guest Wyn Posted May 20, 2008 Report Share Posted May 20, 2008 (edited) Come on Neil, we're all waiting in anticipation! no pressure! I use engine oil as advised by the Company that rebuilt my gearbox. Wyn Edited May 20, 2008 by Wyn Quote Link to post Share on other sites
TIMS Posted May 20, 2008 Report Share Posted May 20, 2008 Yup, very interested. Overdrive Repair Services told me Engine oil with 6k miles changes (every other engine oil change). Regards Tim Quote Link to post Share on other sites
EliTR6 Posted May 20, 2008 Author Report Share Posted May 20, 2008 By engine oil do you guys mean standard 20w50? Thanks! Quote Link to post Share on other sites
Tom Fremont Posted May 20, 2008 Report Share Posted May 20, 2008 I've never had a problem with any of the oils I've used in O/D gearboxes: 80/90 GL5 EP, SAE 50W Non-detergent, and SAE 30W Non-detergent which is recommended by Quantum Mechanics ( - see the website for critique of multi-grade motor oils www.quantumechanics.com ). However, I don't race them Quote Link to post Share on other sites
TIMS Posted May 20, 2008 Report Share Posted May 20, 2008 Eli Yes, in my case Millers Classic 20/50 in 20litre tubs. ORS told me that ideally the overdrive should be running in ATF (Automatic Transmission Fluid) and anything heavier was a compromise. However the gearbox without overdrive would be happiest with Hypoy 90. Their compromise is 20/50 but regularly changed (with which I have no problem having cut the requisite hole in the gearbox cover which has a plate over it fixed with self tappers, so that I can access the filler plug). Regards Tim Quote Link to post Share on other sites
marvmul Posted May 20, 2008 Report Share Posted May 20, 2008 Just to correct this: Triumph specified EP oils in gearbox and diff with or without overdrive. If you have fitted a diff drain plug, renew the oil whenever you do the gearbox, otherwise you are restricted to topping up only. Jerry Everyone believes who he wants to, and maybe it's not a big mistake to use EP oil in the Triumph (o/d)box, but I've always heard that the necessary sulphur content in the EP additive will eat soft metals like synchro rings and bushes, causing difficult and harsh gearchange and worse things. Quote Link to post Share on other sites
Guest ntc Posted May 20, 2008 Report Share Posted May 20, 2008 By engine oil do you guys mean standard 20w50? Thanks! Yes Quote Link to post Share on other sites
RogerH Posted May 20, 2008 Report Share Posted May 20, 2008 Hi Folks, just to add a few more bits to this old O/D chestnut. 1 The Overdrive OEM states that EP oils should not be used as the centrifugal forces may seperate the ingredients and possibly block various oil ways. However modern EP oils probably don't seperate as easily as those in 1952!!! However Triumph recommend EP oils!!! 2. Straight engine oils, magnatec, duckhams etc may froth causing the O/D pump to go silly. 3. Ep80/90 oil may have trouble getting through the pump O/D system so may give a sluggish action/engagement, however conversely when working may produce too much pressure. 4. Most 30/40/50 grade gearbox oils appear to work well with many accounts of perfect working for the life of the gearbox/OD (100k miles etc). 5. Castrol XXL (SAE40) works well with no known problems And Prescott was excellent even if it was bl**dy cold Friday & Saturday night - mind you a big fire certainly warms the old toe nails. Tom's link is very interesting - ceratinly worth a look). However like all things there will be diehard supporters of every known mixture of oil stuffed in every moving part - best of luck to you all!! Roger Quote Link to post Share on other sites
BrianC Posted May 21, 2008 Report Share Posted May 21, 2008 (edited) Most 30/40/50 grade gearbox oils appear to work well with many accounts of perfect working for the life of the gearbox/OD (100k miles etc).However like all things there will be diehard supporters of every known mixture of oil stuffed in every moving part - best of luck to you all!! Many years ago I was advised to use straight 50 grade, so bought a large quantity of Comma 50. This seemed to work well in three cars but I never used it for high enough mileage to guarantee it. However, operation of the overdrive was fine and instantaneous(ish ) and whilst some might say a lighter grade should be used in a colder climate, I drove my cars all year round regardless of temperature . It's probably more important to change the oil more frequently if using engine oil of any kind, rather than EP, so will probably use the 50 grade in Lynda's TR4A as I've no idea what's in there at present. Since it leaks profusely, I'll just top it up from time to time provided there is no deterioration in operation, and then change it every year or so (can't remember what the recommended drain-and-change interval is - just checked and it's 12,000, so I guess about 6,000 should be safe with non-EP). On the other hand, the gearbox and overdrive in my TR3A were rebuilt by TRGB and filled with EP (can't remember if it's 80 or 90 grade) so it makes sense to continue with this. Again, overdrive operation is slick at the moment but if the use of EP causes problems down the line at least I will have stuck with the rebuilder's recommendation. I suspect such problems would only occur after a fairly high mileage so is unlikely to happen within my lifetime (although I'll try to put as many miles on the clock as I can afford ). And Prescott was excellent even if it was bl**dy cold Friday & Saturday night - mind you a big fire certainly warms the old toe nails. We thought you might all be a little cool and felt so guilty in our nice warm B&B next door Edited May 21, 2008 by BrianC Quote Link to post Share on other sites
jerrytr5 Posted May 21, 2008 Report Share Posted May 21, 2008 Everyone believes who he wants to... It's not a question of belief, Marvmul, I was merely stating a fact, as your previous posting may have inadvertantly misinformed some forum readers. You can use mashed bananas for all I care Quote Link to post Share on other sites
JohnC Posted May 21, 2008 Report Share Posted May 21, 2008 Everyone believes who he wants to, and maybe it's not a big mistake to use EP oil in the Triumph (o/d)box, but I've always heard that the necessary sulphur content in the EP additive will eat soft metals like synchro rings and bushes, causing difficult and harsh gearchange and worse things. BTW, back in 2003 a Penrite technical guy (Tony Lawton) told me that Penrite oils did not have an adverse impact on white or yellow metal. He was aware of the issue, but said that as far as he was aware no major oil manufacturer's formulation still had this problem. It's possible of course that a) Penrite has gone backwards since then, or b ) Australia has/had uniquely benign formulations (yeah, right!). My suggestion is that before perpetuating what may now be old & wrong data it might be worth contacting an oil company as I did. Cheers, John PS Are mashed bananas better than sawdust? Quote Link to post Share on other sites
Guest ntc Posted May 22, 2008 Report Share Posted May 22, 2008 (edited) Hi Guy, I reckon that ntc probably has a very valid viewpoint on this one, and I'm looking forward to his explanation with considerable interest. It's always good to learn new stuff ! Cheers, Alec Hi Guy’s I will try to explain the reasons for using Mobil 1 engine oil in a triumph overdrive gearbox, I am passing this information on from a friend and neighbour in our village. This gentleman has worked and developed triumph transmissions for over 30 years, he was a former partner in one of the most respected TR trading companies in the world and was sourced by many other TR dealers. I can not and will not name this gentleman so please don’t ask. He has rebuilt numerous transmissions for me and hopefully will do again but only because I know him. Right then to the oil. This guy spent many hours testing and developing in both race and road use and his conclusion was to use Mobil 1 20/50 engine oil. His brief explanation was that the viscosity of engine oil was based on the temperature that was needed by the engine the transmission runs at far lower temperature so the oil stays thicker and the small amount of detergent that is used in Mobil 1 kept the oilways clean in the overdrive and the gearbox in normal use was adequately lubricated. If used for high performance or race the gearbox had to have the oil changed more frequently. His experience and knowledge has proved this to be correct. Regards, NTC. Edited May 22, 2008 by ntc Quote Link to post Share on other sites
BrianC Posted May 22, 2008 Report Share Posted May 22, 2008 Can I just add a note of caution regarding the use of modern versions of any oils historically proven to be successful? The brand names may be the same but the formulations may not - especially with multigrades (e.g. controversy over old and new forms of Duckham's 20/50). Caveat emptor! And yes - I guess this could also apply to 'straight' 30, 40, 50 grades, but I'm happy to continue using my 30 year-old stock. Quote Link to post Share on other sites
Alec Pringle Posted May 22, 2008 Report Share Posted May 22, 2008 Fair comment on the Mobil 1, it's perfectly plausible logic - more to the point, if it works in practice then don't bother trying to knock it down with theory . . . Brian's caveats are equally reasonable too, the brand that worked well in one decade may not be so appropriate a decade and two reformulations later . . . Which brings us back to the warranty situation, as in there's little to be lost (and possibly a lot to be gained) by following the instructions of the man who builds the unit - certainly whilst the warranty is in force. Mind you, engines and gearboxes will run on damn near any lubricant - the question is how well, and how long. Back when I was running a 'works' team, one championship went down to the wire, everything hinged on the last race on a very fast circuit. Sh*t or bust. We replaced the hub bearing grease with ultra-light pushbike stuff, and the engine 'box and diff oil with SAE 10 lightly dosed with Mike Bingley's silicones - minimal drag to gain an extra couple of horses and an extra couple of mph down the straight. It worked, we cleaned the board, but two laps more and we'd have been sunk. A lot of expensive metal went into the skip the following week ! Cheers, Alec Quote Link to post Share on other sites
TR6 Poor Posted May 23, 2008 Report Share Posted May 23, 2008 I just follow the original owners manual, no problems yet. Cheers Quote Link to post Share on other sites
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