Limitless Posted February 19, 2020 Share Posted February 19, 2020 Hi folks, going to change my oil to the Motul 75W/140 on my 2018 420r LSD diff. Having a search around on here the holes seem to differ but what holes are what? I would assume the one with the red circle is for filling and the blue circled one for draining or have I got that completly wrong? Plus, what is the yellow circled one for. I can't see it on mine, the bracket for the floor is in the way. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted February 19, 2020 Member Share Posted February 19, 2020 Yes, they vary: recent discussion."Which fill hole?".Jonathan Link to comment Share on other sites More sharing options...
K7 VCT Posted February 19, 2020 Share Posted February 19, 2020 Perhaps speak to Phil at road level and race Transmissions in kent. They have magic oil for lsd use.... Link to comment Share on other sites More sharing options...
ChrisC Posted February 19, 2020 Share Posted February 19, 2020 Fill hole is blue, if you follow the manuals recommended 0.8ltr fill it won't overflow. Link to comment Share on other sites More sharing options...
ChrisC Posted February 19, 2020 Share Posted February 19, 2020 There is no drain hole, you will have to suck the oil out. Link to comment Share on other sites More sharing options...
Wilts North AR Posted February 19, 2020 Share Posted February 19, 2020 Have not a clue what the red plug is for. But the blue one is the fill plug. Pour it in there till it dribbles back out. My late 2012 BMW LSD does not have either of the two upper plugs.So you will have to extract the old oil unless it is the same spec as the replacement oil.There has been conversation about BMW LSD oil levels after my lengthy thread about output seal leakage. Rest assured the correct oil level as above will not cause the seals to leak unless they are either (a) not fitted correctly or (b) an early type. Which in your case (b) is not so.Nothing less than a 70w-140 will suffice in the BMW LSD.https://www.lotus7.club/forum/techtalk/bmw-differential-have-you-had-oil-leaks-output-seals Link to comment Share on other sites More sharing options...
ChrisC Posted February 19, 2020 Share Posted February 19, 2020 The recommendations for the manual of 0.8 ltr, if you fill with that amount it won't dribble out. Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted February 19, 2020 Share Posted February 19, 2020 The red circled hex socket bolt is the top cover attachment bolt, inset to avoid deDion tube intrusion. The yellow I think is where the vent hole is located. Link to comment Share on other sites More sharing options...
Limitless Posted February 20, 2020 Author Share Posted February 20, 2020 Thanks for that guys. I knew about sucking it out from recent threads here but wanted to be sure about the drain/fill holes. Link to comment Share on other sites More sharing options...
Area Representative Geoff Brown Posted February 20, 2020 Area Representative Share Posted February 20, 2020 So at long last CC have changed the oil quantity for the BMW LSD diff. My build manual stated to top up the diff until it dribbles out which makes a total of just over 1L.CC must have been conscious of the possibility of output seal leakage so reduced the quantity to compensate.I ask the question then, when the diff is fitted to a BMW does the service instruction state 0.8L or fill till it dribbles out?My diff is not due an oil refresh for another few years as I change my LSD oil every 5 or 6 years, so I will put in only 0.8L next time round. Having changed the output seals some four years ago I have never since had a leakage problem. The originals failed in three years. Link to comment Share on other sites More sharing options...
ChrisC Posted February 20, 2020 Share Posted February 20, 2020 You just can't compare that diff in a BMW to the Caterham adaptation. The back plate with the drain plug isn't a BMW part, so oil quantity, and fill procedures are going to be a different process. What you need to consider is your Caterham BMW LSD diff is a reassembled differential by Caterham's suppliers, after the BMW casting has been machined to fit, and the internals have been changed to the LSD, so the quality of the end product is dependent on the person doing that work. It's entirely possible the seals where damaged (and not spotted) during that process. As for the official BMW diff fill quantity it depends on spec, but a 168LW diff has .75ltr and 188LW is .8ltr, so Caterham are more inline with BMW now. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted February 20, 2020 Member Share Posted February 20, 2020 What's the access like for the fill hole?Jonathan Link to comment Share on other sites More sharing options...
Limitless Posted February 21, 2020 Author Share Posted February 21, 2020 Access is not easy. I've had to take out the entire boot floor which isn't easy to start with as there is some kind of electrical devise bolted to the honey coned floor for the Petrol sender.Oil is now all out and just waiting for the new to be delivered. Interestingly enough, the oil I dropped out was blue and I wonder if it was 75W/140 to begin with...Pretty sure the old spec EP90 is engine oil colour. Link to comment Share on other sites More sharing options...
ChrisC Posted February 21, 2020 Share Posted February 21, 2020 Sounds like it was already filled with Motul Gear Competition SAE75W140, The Comma stuff they used before 2017(ish) wasn't blue. Link to comment Share on other sites More sharing options...
Limitless Posted February 21, 2020 Author Share Posted February 21, 2020 That's what I thought. Can't do any harm though as the last bit to come out was a bit dirty. Link to comment Share on other sites More sharing options...
ChrisC Posted February 21, 2020 Share Posted February 21, 2020 The real question is what plates does your diff have, I believe there was a time when Carbon plates where tried, and these tend to wear quickly. https://www.lotus7.club/forum/techtalk/270r-lsd-problem Link to comment Share on other sites More sharing options...
dave_h34 Posted February 28, 2020 Share Posted February 28, 2020 They do, and it's good stuff. Prevents the graunching and hopping on low speed tight manoeuvres. Link to comment Share on other sites More sharing options...
K7 VCT Posted February 28, 2020 Share Posted February 28, 2020 Just had my diff reset and serviced by the boys at road and race Transmissions in kent, got a bottle of the magic oil too..... Link to comment Share on other sites More sharing options...
intermanxnorton Posted March 1, 2020 Share Posted March 1, 2020 Whilst talking LSD guys, does anyone know if the Sierra diff. model Titan is suitable for my 140 Supersport. It runs the Mazda 5 speed box. Any help as to suitability would be welcomed. If not what alternatives do I have, and is it straight forward enough to replace.phil. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 1, 2020 Member Share Posted March 1, 2020 What final drive/ diff is in there at the moment? Please add a photo if you don't know.... and is it straight forward enough to replace.If you'd like a copy of the Assembly Guide please send me a Private Message with your email address and details of the Seven.Jonathan Link to comment Share on other sites More sharing options...
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