Rear drive box on mk2 LM |
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swede
Falcone Joined: 10 Dec 2017 Location: west country Status: Offline Points: 57 |
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Posted: 22 Dec 2019 at 23:54 |
I have just drained my rear drive box and gearbox to change the oil for 75w140 and the drive box oil has come out a bit metallic, dark colour too! Has anyone else seen similar? It is ep80 or ep90 coming out, with a dash of slick 50.
Edited by swede - 23 Dec 2019 at 00:01 |
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swede in the shed
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sardineone
Senior Member Joined: 30 Oct 2018 Location: Indiana, USA Status: Offline Points: 443 |
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I've seen metallic in the oil on several occasions from the transmission and the rear drive. A possible contributing factor I learned is that many GL-5 gear oils attack yellow metals like bronze or brass bushings for example. I don't remember where I first read about this. Since then I contacted Mobil One since I had been using their synthetic gear oils and they couldn't verify their GL-5 was yellow metal compatible. Royal Purple brand in the USA states on the bottles that it is compatible with these materials and is what I'm currently using.
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George
One owner 86' Lemans 1000 (member of the family) / BMW R1200ST (current work horse) You are what you have ridden! |
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Brian UK
Moderator Group Joined: 13 May 2014 Location: Surrey Status: Offline Points: 17641 |
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You could always try one of the Redline products.
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Brian.
Better 5 minutes late in this world than years early in the next. |
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sardineone
Senior Member Joined: 30 Oct 2018 Location: Indiana, USA Status: Offline Points: 443 |
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Not my original source, but some info on the subject of GL-5 oils. https://www.machinerylubrication.com/Read/28958/ep-additives-effects
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George
One owner 86' Lemans 1000 (member of the family) / BMW R1200ST (current work horse) You are what you have ridden! |
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swede
Falcone Joined: 10 Dec 2017 Location: west country Status: Offline Points: 57 |
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That's interesting as an 'ep' oil, which was essential in hypoid axles which guzzi drive boxes are, contain sulphur and, if my memory is correct, magnesium. So now; is there any bronze or copper type metals in the D. Box or G. Box and, is there any sulphur or any 'corrosive to copper' materials added to fully synthetic oils? : The sulphur was added to stop the steel gear teeth welding and tearing each other locally when the extreme pressure broke through the oil film. Perhaps the fully synthetic is so much better that it never does break through?
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swede in the shed
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sardineone
Senior Member Joined: 30 Oct 2018 Location: Indiana, USA Status: Offline Points: 443 |
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To further clarify, I've been using synthetic gear oil in my transmission & rear end for many years and miles. Memory is soft whether I started on a GL-4 oil. I also didn't too closely analyze the metal in the messy gear oil, but seemed to have a yellow tint and was present well over break-in miles for sure.
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George
One owner 86' Lemans 1000 (member of the family) / BMW R1200ST (current work horse) You are what you have ridden! |
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Mike H
Senior Member Joined: 21 May 2014 Location: East Anglia Status: Offline Points: 8733 |
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I didn't see anything that colour when I took mine apart. LM1. I also ended up using SAE 85-W140, plus molyslip, as was recommended on the club forum. You may have to take yours apart to find out where the metal is coming from. |
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"Chicken nuggets don't dance on a Tuesday."
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1down5up
Senior Member Joined: 29 May 2016 Location: Australia Status: Offline Points: 123 |
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Nothing bronze or brass in rear drive, 5 speed gearboxes did have a brass bearing(and it's expensive....)
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swede
Falcone Joined: 10 Dec 2017 Location: west country Status: Offline Points: 57 |
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Miller Oils assure me there is nothing detrimental to yellow metals in their oils so Miller fully 75w140 is going in the G/box and drive box. On the other points I said about, I slept on it, and all was clear this morning. As there is no oil seal between the drive box pinion bearings and the drive shaft housing (swinging arm leg) there is nothing to stop anything from that tube going straight through the pinion bearings into the drive box housing. As I used high molly content grease (recommended for dry splines), when I reassembled it, that's where the dark colour came from and that made it look more metallic than it actually was. Bit worrying that any debris from the UJ and spline joints can get down into the bottom though isn't it? Anyway, I've washed it out with brake clean, flushed it with thin oil and now the FS 75w140 can go in! : I think regular oil changes will be done from now on. Thanks for your response to my thoughts.
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swede in the shed
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Mike H
Senior Member Joined: 21 May 2014 Location: East Anglia Status: Offline Points: 8733 |
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Not the UJ, because that is in front of the swingarm support bearing, which is blind (sealed). The driveshaft, yes, 3 splined joints (back of UJ, and the coupling sleeve to mate with the pinion). You are supposed to have that out for a bit of a clean up and regrease occasionally, but apart from the horrible manky dark brown grease that a PO had put into mine, I don't remember anything else especially nasty. But is worth a thought. NB: there is a paper gasket between FD and swingarm, this is square, four stud holes at the corners, and a large round hole in the centre, and in the edge of this hole a slot, kind of thing, this must go to the bottom as there is a drain channel there for oil to get back into the FD case if it has gone forward into the swingarm tunnel. |
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"Chicken nuggets don't dance on a Tuesday."
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swede
Falcone Joined: 10 Dec 2017 Location: west country Status: Offline Points: 57 |
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Yes, you're right about the uj ;anyway, I put the apparent contamination down to my over exuberance with the molly grease last time and just brushed it on the splines. I also found rust on the roof of the tube, I cleaned it off a bit (it was only surface from condensation I think) and gave it two sprays with chain lube, it won't run off. All back together now, just waiting to register it as historic so I'll get free road tax!
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swede in the shed
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Bushymusic
Senior Member Joined: 25 Jul 2015 Location: London Status: Offline Points: 420 |
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Hi all, just changing the gaiter that protects the UJ (cleaned the UJ and regressed of course) and I've had the swing arm off and the bevel box detached. I strangely have that paper gasket mentioned above (which has torn) it isn't mentioned on the 850 transmission drawing & Gutsbits says they are obsolete as there are 2 x rubber gaskets that go either side of the tapered roller bearing (one between bevel box & swing arm). any thoughts on making one of not bothering with it?
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Black and gold Le Mans mk2 1981
when I'm not sitting on my hands we're a work in progress. |
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Barry
Senior Member Joined: 02 Mar 2015 Location: Oxford Status: Offline Points: 2811 |
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Gutsibits list these obsolete items (5 in stock_ - their #TRA12900 - GU12352900
Apologies - I don't have an opinion (or knowledge) on whether you need use on the LM2 - just know that I was in a similar position to you, with a 1000SP, and had to research the bit. |
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Ken-Guzzibear
Moderator Group Joined: 13 May 2014 Location: Sileby Leics Status: Offline Points: 9454 |
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Manual tells you EP90 + moly in a bevel box having managed well over 200k on oem one only swapped it as it was a convert bevel and very high geared so got a swing arm and standard one.
The oem stuff works a Guzzi engine was made to manage 100k miles on basic servicing so why mess with what works. Never understand that.
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The Older i Get, The Better I Was
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Stevex
Senior Member Joined: 24 Nov 2020 Location: North Yorkshire Status: Offline Points: 406 |
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What Ken said.
EP90 and moly here too.
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