KM Posted September 23, 2018 Share Posted September 23, 2018 After a nice run to and from the RBRR drivers' meeting decided to check oil levels in diff and gearbox today. On undoing the gearbox fill plug oil started coming out quite quickly and it looks full of fine bubbles, see photo. Any ideas what is going on? Car was on the level. It has an overdrive that goes in and out nicely. Quote Link to comment Share on other sites More sharing options...
Hogie Posted September 23, 2018 Share Posted September 23, 2018 HI Kevin, most oils will produce a small amount of fine bubbling. What type of oil do you use. Engine oil 20/50 etc may contain detergent and give a great deal of foaming. Roger Quote Link to comment Share on other sites More sharing options...
KM Posted September 23, 2018 Author Share Posted September 23, 2018 Hi Roger, no 20/50 in gearbox, using a hypoid oil EP80/90. Will be putting a lot of fresh oil back in as quite a bit came out when I removed the drive for the angle drive for the speedo. The speedo seized solid yesterday damaging the angle drive.When the gearbox was last topped off I leave the plug out for a few minutes to let any extra drain out (and so it doesn't run down my arm as I squeeze it between the exhaust and chassis to reinsert the plug). The only way the volume of oil can grow is if some of air is mixed in it and retained. I guess this oil will rise to the top and the oil lower down in the gearbox will be more air free. I am a bit concerned as have never seen this before. Kevin Quote Link to comment Share on other sites More sharing options...
iggy Posted September 23, 2018 Share Posted September 23, 2018 ive seen this, im pretty sure it was when i drained my A type overdrive box straight after a long run with hot oil, Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted September 23, 2018 Share Posted September 23, 2018 Checking oil levels straight after a run will produce this effect as a) it's hot so has expanded a bit b) it gets an incredible thrashing inside the gear and becomes somewhat aerated, further increasing the volume. So inevitably it will have "grown" from when you carefully topped it up to the mark cold and will overflow when the level plug is removed. Gearbox and diff levels should be checked when cool and after the car has been stationary for a good 30 mins. If you are changing the oil however, as with engine oil, this is best done right after a short run so the oil is warm and free flowing and any small particles of debris are still in suspension. Nick Quote Link to comment Share on other sites More sharing options...
KM Posted September 24, 2018 Author Share Posted September 24, 2018 The car had stood overnight before the plug was removed so the oil and gearbox were cold. Quote Link to comment Share on other sites More sharing options...
daver clasper Posted September 27, 2018 Share Posted September 27, 2018 There is a breather somewhere on the box I understand. Could this blocked, causing it to pressurise?. Dave Quote Link to comment Share on other sites More sharing options...
Dannyb Posted September 28, 2018 Share Posted September 28, 2018 Yes the breather is on the top plate. Should have a black plastic cap on it. After the last rbrr mine was leaking oil all over as this had become blocked. I have since fitted a copper pipe to the breather which then runs down the side of the box. Quote Link to comment Share on other sites More sharing options...
KM Posted September 28, 2018 Author Share Posted September 28, 2018 Do you have any pictures where the breather hole might be? Happy to drill a small hole, that could be plugged with a grommet, through the tunnel for access. Quote Link to comment Share on other sites More sharing options...
KM Posted September 28, 2018 Author Share Posted September 28, 2018 It's a Mk2/3 with OD if that makes a difference. Quote Link to comment Share on other sites More sharing options...
sparky_spit Posted September 28, 2018 Share Posted September 28, 2018 Is it a single rail gearbox or a three rail one? If a single rail, the breather is (as Danny says) is a 3/8" dia black domed plastic thing. It's on the steel top plate of the gearbox which also has the switch for inhibiting overdrive selection when in 1st/2nd gear (with two green wires coming from it). The black plastic breather pulls out and comes apart by pulling the end off. There is a 1mm square channel running up the inside of the breather which needs to be clear. It's not something you could get to through a hole cut in the tunnel cover though. If it's a three rail box, then I don't know where the breather is, but someone else will.... Quote Link to comment Share on other sites More sharing options...
KM Posted September 28, 2018 Author Share Posted September 28, 2018 I think it is a three rail box. I found a pic of one and have labelled the only two bits that look like they may be breather holes. Any ideas? Quote Link to comment Share on other sites More sharing options...
sparky_spit Posted September 28, 2018 Share Posted September 28, 2018 Yes, that's not a single rail box. I've never actually had a 3 rail in my possession but that has three rails so must be one! Those things you have arrowed look more like captive/nuts/holders for detents/springs, but as I've never seen one in the flesh I can't be certain. You need Rob or Nick or someone else who knows what they are talking about to advise. Sorry I can't be of more help. Quote Link to comment Share on other sites More sharing options...
KM Posted September 28, 2018 Author Share Posted September 28, 2018 Well I eventually found this page on another forum:https://www.triumphexp.com/phorum/read.php?8,891424which has a nice pic of where the vent hole is. Managed to get a paperclip in and bend it over to see how deeply it went in: 30mm (just over an inch in old money). Seems like a reasonable distance to me. I don't think a blocked vent is the problem. And it's point B on the pic of the gearbox above. Any other ideas? Quote Link to comment Share on other sites More sharing options...
RobPearce Posted September 28, 2018 Share Posted September 28, 2018 Sorry, wasn't checking in earlier today. I wouldn't have thought your issue would be breather-related anyway. What you got was, as somebody said early on, normal behaviour immediately after a run, so the question is why isn't your oil settling down as it cools. Quote Link to comment Share on other sites More sharing options...
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