Rear Hypoid Oil

Discussion in 'General Tech Talk' started by hombre, Apr 18, 2008.

  1. hombre

    hombre .020 Over

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    OK, Triumph says use Mobil Lube SHC 95W-90 synthetic hypoid oil in the rear drive... but this doesn't seem to exist anywhere except possibly at Triumph dealers. I have found Mobil 75W-140 synthetic hypoid oil to be readily available... opinions on suitability? :confused:
  2. Sidecar Flip

    Sidecar Flip Turbocharged

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    Tne answer please..............

    Walt:

    I'm gonna tell you where to get it and it's not a Triumph dealer either, plus I'll give you a good substitute and it's not Amsoil either......

    Go to any heavy truck dealer (like Freightliner or Peterbilt) that services heavy trucks. The final drive fill in the Hotchkiss full floater drives in the new Fuller-Eaton and Dana-Rockwell rear ends is 85-90 GL4-5 Full Synthetic Hypoid Oil. They have switched from a sulfur based petroleum oil to a fill-for-life full synthetic. The only time it's changed is if there is an internal failure. It usually comes in 55 gallon drums but I'm sure you can buy a quart, just take along a clean plastic jug. It'll probably cost you about 10 bucks a quart.

    A good substitute and one that's available from any Shell jobber is 85-90 GL4-5 Spirax Hypoid oil. That's what I change my final drive on my R3 with. You can buy it by the pint, quart, gallon, fives or 15 gallon drums. I get it in 5's. I use it in the MFWD units on the 4wd farm tractors. Spirax is also available in 85-140 GL4-5. The major difference in the 85-90 and the 85-140 is the 140 hold it's viscosity grade better under shear but at low temperatures, it resists flowing. If you are going to ride the bike in cold weather, I'd recommend the 85-90. The 140 won't provide good boundary lubrication is sub freezing temperatures.
    Last edited: Apr 18, 2008
  3. hombre

    hombre .020 Over

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    Thanks, Flip... I figured you would know.

    The Mobil1 75W-140 SuperSyn is also GL-5... isn't this the same thing?
  4. Sidecar Flip

    Sidecar Flip Turbocharged

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    GL5 is just like an API rating but the test is for shear and boundary lubrication, not shear and grade degradation. The higher the number, 5 being the best consumer grade available, will provide the best shear and boundary protection for the hypoid profile gearing. Remember, the teeth of the pinion actually slide along the mating teeth of the ring gear as they transmit horsepower and torque. The lubricant has to provide a boundary coating, conduct heat and reduce friction while resisting shear. Besides, the fill in the final drive is negligible so it's wise to run the highest quality (highest GL rating) you can get.

    It is possible to get a GL6-7 rated hypoid oil, but it's aerospace grade and your conventional ring and pinion isn't going to benefit from any higher than a GL5 rate.

    If, you do run an 85-140 GL4-5 Hypoid oil in colder weather, you will run the risk of seal failure as well. At below freezing temperature, the 85-140 will be so viscous, that it could break a pressed in seal loose.
    Last edited: Apr 18, 2008
  5. hombre

    hombre .020 Over

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    I appreciate the education. I've got a Qt of the Mobil 75W-140 (since it was readily avaiable) and now I'll use it with confidence. I just wonder why Triumph specifies something Mobil doesn't seem to make... straight Mobil 95W.

    Maybe it's a Brit thing? :D
  6. Sidecar Flip

    Sidecar Flip Turbocharged

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    Because Mobil bottles and brands it specifically for Triumph just like the Mobil 4TRacing that's only available at the dealer, for a price.

    I just found out the other day that Rotella T 15-40 XLA is JASO-MA applicable and tested. For everyones information, JASO-MA stands for Japanese Automotive Standards Organization, Motorcycle Applicabe. There is now a JASO-MA2 rating. That rating has to do with shear under extended drain intervals like Triumph and other manufacturers are mandating. So long as you decrease the drain interval to something more sane, like 5K instead of 10, JASO-MA rated oil is fine.

    I'm not saying I would recommend 15-40 Rotella T-XLA for the R3 simply because the Rock needs a 20-50 JASO-MA or MA2 oil. There is no oil cooler and oil temps run pretty high. If Rotella came in a 20-50, I'd be running it in the R3. I do run 15-40 Rotella in my T100 Bonnie simply because the Bonnie is air/oil cooled with a large, OEM oil cooler.

    I don't want this to turn into an oil debate.

    One thing I've found is that everyone has a favorite brand and their brand is the best and bla-bla-bla. I go on API and GL ratings as well as lab tests. Besides, I always to a spectroscopic analysis on every second change so I know just how the lube is behaving and what metals are present in the drain oil.
  7. hombre

    hombre .020 Over

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    Yes, that would explain why I can't find it... no doubt you're right! I always pre-heat my R3 in sub zero tems, so I think the 75W-140 will be fine.

    No oil debate here, I really appreciate all the good info. Thanks! :cool:
  8. Rocket727

    Rocket727 Standard Bore

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    Hombre,

    In your original post on this topic, you stated that Triumph says use "95W/90". I suspect that you mistyped and meant 75W/90. My Triumph service manual says use "Mobilube 1 SHC 75W/90 fully synthetic hypoid oil or equivalent". I guess this manual was printed at least four years ago.

    Anyway, I changed my bevel box oil a couple of days ago and used Mobil 1 fully synthetic gear lubricant 75 W/90 that, according to the bottle, exceeds GL-5 requirements. I found this at AutoZone and paid $8.99+tax qt.

    I was talking to a Mobil distributor a few days ago and he said that Mobil has eliminated some of the description jargon in its lubricant names for simplification. I can't find any gear lubricant name on the Mobil website that has "hypoid" as part of its name and see no other lubricant that is better than this at Mobil. As you said they have the 75W/140.

    Well, it's in my bevel box and my quandary now is whether to switch to the Mobil 1 Racing 4t 10W/40, which I also saw at AutoZone at around $8.00 qt., rather than the dealer's 15W/50 ripoff. I live in the RDU area of NC and it does get hot in the summer.
  9. Sidecar Flip

    Sidecar Flip Turbocharged

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    If it was me, and it's not, I'd use a 20-50 full synthetic SG or SG-JASO-MA or MA2 applicable oil. For one thing, the R3 has no oil cooler and the transmission and engine share the same oil. If it was just the engine, you could use an SG rated 20-50 but the gear sets and bearings in the gearbox will shear down the SG rated oil much faster than the JASO-MA rated oil. By shear, I mean the gears and the bearings will cause the viscosity index to drop, especially at the OEM recommended 10K oil change interval.

    I'm using Rotella T 15-40 in my new bike but I'm changing the oil every 1500 miles. Interestingly, Rotella has been tested by Shell and meets the JASO-MA standard even though it isn't stated on the bottle.

    Whatever oil you decide on using, make absolutely certain it has no molybdenum disulfide or 'Moly' in the additive package. Wet clutches fail quickly with a Moly additive.

    There is a lot of hoopla about oil and especially motorcycle specific oil but the fact is (and I can back it up with test reports) that so long as you don't extend your change intervals and keep an eye on the heat cycles, any high quality automotive motor oil will do fine in a bike so long as it don't contain Moly.

    It's also a proven fact that motorcycle specific oils cost appreciably more per quart than automotive oils. Let your wallet and common sense be your guide.

    If, indeed I was to adhere to the OEM's 10K change interval, I'd run either Amsoil 20-50 SG-JASO-MA or the branded for Triumph Mobil 4t Racing. I run the Amsoil but I still half the change interval. I just keep the drain oil for my riding lawnmower, rototiller, push mower and my wife's car.:D
  10. Rocket727

    Rocket727 Standard Bore

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    The Mobil 1 Racing 4t 10W/40 (the oil that I saw in quart size at AutoZone) is one of the recommended oils in the Triumph service manual. I suspect that the dealers , at least in this area, stick to the same Racing 4t 15W/40 because, as far as I know, that viscosity only comes in the 5 litre size. If you don't ask for it, they keep what is left after they do a change on the Rocket. That means opening two containers which leaves at least three + liters(about $40 worth of oil leftover) that you probably won't be offered unless you ask for it. That, among other reasons, is why I'll do my own changes.

    My concern is not with the quality of the oil (the racing 4t 10W/40) but whether the lighter oil is really meant for cooler climates. NC is sorta on the border line but I suspect on those real hot days the 15W/50 is a better choice. The manual doesn't break down the viscosity/temperature recommendations like some vehicle manuals do.:)
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