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Thread: r380 oil guru's question.

  1. #1
    Join Date
    Sep 2007
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    544

    r380 oil guru's question.

    Gear box oil is up for a change and found recommended oil hard to find. In comparing traditional gearbox oil with Syntrans seems the viscosity at various temps seem to be very similar in viscosity. Wondering if I am reading this correctly as considering using penrite outback hardened 80w90 which seems to be very similar in viscosity and not an issue with brass etc. Viscosity may be a little thicker when hot

    80w90
    TYPICAL DATA
    Colour Blue
    Density at 15C, kg/L 0.894
    Viscosity, Kinematic, cSt at 40C 152
    Viscosity, Kinematic, cSt at 100C 15
    Viscosity Index 99
    Viscosity, Brookfield at -26C 53,800
    Phosphorus, Mass % 0.06

    Syntrans
    Viscosity, Kinematic100C ASTM D445 mm/s 11.9
    Viscosity, Kinematic 40C ASTM D445 mm/s 64.4
    Viscosity, Brookfield @ - 40C (75W)
    DIN 51398 mPa.s (cP) 18000
    Pour Point DIN-ISO 3016 C -45
    Density DIN EN ISO
    12185
    g/ml 0.837


    Have I missed something??

  2. #2
    Join Date
    Jan 1970
    Location
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    Totally different viscosities when cold!
    Look at the viscosity and VII. r380 oil guru's question.
    152 vs 64@40!
    I'm in the phone atm but if we plugged those numbers into a viscosity calculator the 80w-90 would be like treacle at close to zero, and probably bugger the 'box as it possibly wouldn't flow through the galleries fast enough to lube the bearings

    That 80w-90 would be bloody awful, don't skimp on using a decent fluid in that 'box.

    Plenty of posts and threads on here on what is used and what works well.

  3. #3
    Join Date
    Jan 1970
    Location
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    1,475
    I have just changed the oil in my R380. I run Penrite in everything else in my Defender, apart from the R380 which I have always used Castrol Syntrans 75W-85 full synthetic.

    The R380 was due for a change so I decided to try the Penrite Progear 75W-85.

    Now I am unable to select second when the box is cold. So this weekend I will be swapping back to Castrol Syntrans 75W-85. It's not cheap - at about $33 for 1 litre at Repco. But it's worth it in my opinion, My box shifts super smooth at all temperatures using the Castrol Syn Trans.
    Andrew
    1998 Landrover Defender 300Tdi 130 HCPU Expedition
    1972 Peugeot 504 Sedan - Daily Driver

  4. #4
    Join Date
    Sep 2007
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    544
    Quote Originally Posted by 86mud View Post
    I have just changed the oil in my R380. I run Penrite in everything else in my Defender, apart from the R380 which I have always used Castrol Syntrans 75W-85 full synthetic.

    The R380 was due for a change so I decided to try the Penrite Progear 75W-85.

    Now I am unable to select second when the box is cold. So this weekend I will be swapping back to Castrol Syntrans 75W-85. It's not cheap - at about $33 for 1 litre at Repco. But it's worth it in my opinion, My box shifts super smooth at all temperatures using the Castrol Syn Trans.
    Thanks, exactly what I was after

  5. #5
    Join Date
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    Location
    Canberra
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    When I had my D1 I had Syn trans in it.

    Ok on -5 Canberra winter mornings and also Ok on +40 Canberra Summer afternoons.

    Just go with SynTrans - never saw it as high as $33 a litre but then I buy oils when on special.
    REMLR 243

    2007 Range Rover Sport TDV6
    1977 FC 101
    1973 Haflinger AP700
    1971 Jaguar V12 E-Type Series 3 Roadster
    1957 Series 1 88"
    1957 Series 1 88" Station Wagon

  6. #6
    Join Date
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    Quote Originally Posted by 86mud View Post
    I have just changed the oil in my R380. I run Penrite in everything else in my Defender, apart from the R380 which I have always used Castrol Syntrans 75W-85 full synthetic.

    The R380 was due for a change so I decided to try the Penrite Progear 75W-85.

    Now I am unable to select second when the box is cold. So this weekend I will be swapping back to Castrol Syntrans 75W-85. It's not cheap - at about $33 for 1 litre at Repco. But it's worth it in my opinion, My box shifts super smooth at all temperatures using the Castrol Syn Trans.
    X2
    Cheers,
    Mark F...
    Vk3KW / VK3ZMF

    2000 Disco 2 Td5 Manual - Current
    197? Range Rover - Petrol (and LOTS of it) - gone
    1973 SWB SIII Diesel - gone
    1968 SWB IIA Petrol - gone
    195? SI - Petrol - gone
    Balance Trailers forward fold camper trailer.

  7. #7
    Join Date
    May 2007
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    in the wild New England, NSW
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    I know that Syntrans is expen$ive - but much, much longer oil change intervals are recommended.
    REMLR 374
    VKS Mob 3258

  8. #8
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    The only problem with Syntrans is it shears quite badly within 20000 kms
    Requiring a change interval of no more than 20000
    On the advice of Rick I used motul 300 an absolute bitch to change when its cold but magic once it warms up

  9. #9
    Join Date
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    Quote Originally Posted by djam1 View Post
    The only problem with Syntrans is it shears quite badly within 20000 kms
    Requiring a change interval of no more than 20000
    On the advice of Rick I used motul 300 an absolute bitch to change when its cold but magic once it warms up
    Duane, that just goes to show how idiosyncratic the R380 is as I found Gear 300 better when cold than Syntrans!
    Unless Motul have reformulated in the last four years, which could've happened?

    It definitely survives longer than Syntrans, with a much better change in high ambient/high load conditions

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