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Thread: EP90 vs EP120?

  1. #1
    Join Date
    Apr 2021
    Location
    SF Bay Area
    Posts
    234

    Default EP90 vs EP120?

    Hey folks!

    Any US based LR owners can recommend a US supplier of good EP90 gear oil?

    I can't seem to find the coveted Castrol EP90 1 liter tins here. Also, does anyone have good recommendations for another (easier to find) brand? I hate to spend $20 + International shipping (per can)for something that will just slowly end up leaking on my driveway.I just checked the manual and with the main gearbox, transfer box and 2 differentials...I have to get minimum 7.5 liters of this liquid gold.

    The other question I have is - well, my local autoparts store only has a generic EP120(GL4) gear oil. I'm in SF Bay Area, so it doesn't get that hot or cold...probably 50F-85F all year. I read the 120 weight is recommended for hard wearing or extreme conditions(in the differentials). I put the 120 in my differentials about 1.5 months ago. After a few 30 minute drives, I developed a front diff oil seal leak. Could just be coincidence. But I wonder if somehow the higher viscosity is somehow making more pressure and blew it out? What do you folks think?

    I've ordered some new seals(along with some U-Joints while I'm at it) and looking to get EP90 this time.

    Last question: Is it possible to change the rear output bearing on the front differential from the prop-shaft side, with the diff in the car? I mean, can it come out strictly from the rear (without removing the axles, gear assembly, etc and tapping/pressing it out from the front?)

    [Edit] This last part sounds impossible. Cross section image attached, with bearing race highlighted in yellow.


    Any thoughts?
    Attached Images Attached Images  
    Last edited by vlad_d; 12-20-2021 at 03:00 PM.
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    1973 Series 3, 109

  2. #2
    Join Date
    Oct 2011
    Location
    Mountains of Western Pennsy.
    Posts
    592

    Default

    Hmmm... Try using 75/90 (or 80/90) Lucas Oil, it's good stuff, I use it in diffs, transfer cases and, transmissions. Why change a bearing because of an oil seal leak? Unless there's a lot of play in the shaft. First check your axle vent and be sure it's clear, if the vent's clogged it will build up pressure and cause any seal to leak. Changing bearings on the diff INPUT shaft will require you to take it all apart and set everything back up (back lash) when you're done. The seal itself can be changed without tearing everything apart. Also, heavy oils in the right conditions can build up excess heat resulting in excess pressure. I only have to worry about heavy oil in my diffs as my '76 S3 has a massive LT95 trans/transfer case combination (it's a one piece affair), with overdrive. It uses 20-50 engine oil and has an internal oil pump.

  3. #3
    Join Date
    Apr 2021
    Location
    SF Bay Area
    Posts
    234

    Default

    Why change bearing for oil leak?

    Probably won't, now that I thought about it. I had a sqweek develop along with that oil leak. Sounded like it might be coming from that area. I thought it was suspicious. So I ordered new U-Joints, too. While I was at it, I ordered all service-able components in the area. For some reason, everything takes 3 weeks to get to me - and this was exactly like that. I got a call back from my supplier(not Rovers North, for these items) a week after ordering parts that there was a 6-8 day delay. Anyway, time is worth more than an extra $30, so I bought a Timken bearing, too. Why not? I was expecting to take the oil seal off and find a mess. Then what? Wait another 3 weeks for parts? Nah, I ordered the bearing, too. I was worried that maybe it might not be the 120weight oil? Maybe a wobbly propshaft/U-Joint setup enlarged the seal opening? It was a theory...probably wrong. Extra parts go on the shelf, I guess. I'll need them eventually.

    Good tip about the breathers. I did just replace them a few weeks ago(brand new). I'm trying to replace little odds and ends.
    ...┌───────┬──,,
    ...|______OD__|__\\_____
    ...d ..__ .........° |°... | ..__....p
    »»└/ | \────┴──┴/ | \─┘≡
    ..../..@........................@

    1973 Series 3, 109

  4. #4
    Join Date
    Dec 2010
    Posts
    395

    Default

    gawd, vlad & others. .................. this stuff leaks, you refill it about once a year, no prob.
    in the mid-70's land rover issued leather seals on the seals......... that has probably gone the way of dinosaurs but they did last a long time.
    after that you just refilled the boxes, ((most never checked the level)) .............. as a result gold finds in the junk yards !!!
    I do not believe I have ever replace the pinion seal on my series 3 since it was new (1972) ............... ,my advise is, keep the boxes full, drive it like a farmer and if you hear something screwed up ............... fix it!!

  5. #5
    Join Date
    Apr 2021
    Location
    SF Bay Area
    Posts
    234

    Default

    Just got my shipment of liquid gold...$15 each. Can you believe it? I'm going to go broke driving this car!!

    Service manual says to replace this stuff every 2 years or so. Hmmm...someone over at Castrol and Land Rover teamed up for profits, here. I don't like it... I don't like-it-at-all :/
    Attached Images Attached Images  
    ...┌───────┬──,,
    ...|______OD__|__\\_____
    ...d ..__ .........° |°... | ..__....p
    »»└/ | \────┴──┴/ | \─┘≡
    ..../..@........................@

    1973 Series 3, 109

  6. #6
    Join Date
    Dec 2010
    Posts
    395

    Default

    bardahl, i bought a 5 gallon can about 1983. I could tell the rolling resistance was cmaonsiderably less. I'd say change your 90 weight every 5 years or 50-75k miles. unless you get water in it!! or grind some metal.

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