Percy TR6 Posted January 10, 2015 Report Share Posted January 10, 2015 Gents, I'm in the process of trying to service my car myself - for the first time - and this is the second in my forthcoming series of "hmmm, what do I do now?" questions. As the car is up on stands, I thought this would be a good time to look at the brakes, waxoyl the chassis and address the "territory marking" issues while I am at it. I've sorted the drip from the radiator (loose jubilee clip on the bottom hose), the rocker cover (new gasket) and the clutch slave (new unit). I'm now moving back to the gearbox and beyond. I can't see any images attached to the above post so have attached an image from beneath my car. As you will see, the "drain plug" seems to be only screwed in half way......is that normal? It does seem tight but I would have expected it to screw in flush. There's normally a bit of oil round and about but I've wiped it down for the photo! At this stage I don't know if the oil is weeping from this plug or elsewhere or both but this seemed like a good question to start with. I always have cardboard beneath the car in the garage and can confirm that oil leakage onto there has been minimal, but it would be good to reduce it further if I can. I've also attached a photo of the overdrive sump..... Looking at this I assume it needs a new gasket....though it could be oil flowing back from the gearbox I suppose? As always, thanks in advance for the input. Steve Quote Link to post Share on other sites
tr6fan Posted January 10, 2015 Report Share Posted January 10, 2015 I think the gearbox drain plug is fine if it's tight-mine shows threads just like yours. Worth replacing the overdrive gasket as it is not too difficult and you can extract the filters at the same time to check/replace them. hth Phil Quote Link to post Share on other sites
foster461 Posted January 10, 2015 Report Share Posted January 10, 2015 Hi Steve, you will find most of the drain plugs on the TR6 are tapered pipe threads so they only tighten until the bolt stops and some protrusion is normal. You may chase gearbox leaks for the rest of your life so unless oil is pouring out I would just live with it. It can be a challenge to figure out where the leak is and it is often somewhere different from where oil is puddling/dripping. If you clean the whole underside and leave it you may get an idea of what is leaking and see if it accessible but it is likely to be an incurable leak in one of the many interfaces in the grearbox/OD assembly. Stan Quote Link to post Share on other sites
Percy TR6 Posted January 10, 2015 Author Report Share Posted January 10, 2015 (edited) Thanks for the input guys. I decided to order a gasket for the OD sump and in the meantime move on to something simple....replacing the oil. The only problem is I cannot get the sump drain plug to move! Could anyone confirm what size it is? Its a square end and I have tried everything I have in all sorts of sizes but everything seems to slip. The brown book says 3/8" x 18 - is that correct? Steve Edited January 10, 2015 by Percy TR6 Quote Link to post Share on other sites
RogerH Posted January 10, 2015 Report Share Posted January 10, 2015 (edited) Hi Steve, the gearbox drain plug usually has a square head. If the hex head bolt works then leave it. The sump drain plug is a 7/16" AF fit. If a spanner slips off then use Moles wound down tight. They can be tight - but why. Before or after your gasket change (preferably before) wash the gearbox and and OD outer surfaces with brake cleaner aerosol so it is completely clean and free of oil. Spray the GB/OD with chalk http://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.XAerosiol+chalk+spray&_nkw=Aerosiol+chalk+spray&_sacat=0 or NDT Dye pen developer http://www.ebay.co.uk/sch/i.html?_odkw=Aerosiol+chalk+spray&_from=R40&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.XDye++penetrant+developer&_nkw=Dye++penetrant+developer&_sacat=0 Take for a 1 hour drive and see where it is leaking. Roger Edited January 10, 2015 by RogerH Quote Link to post Share on other sites
graeme Posted January 10, 2015 Report Share Posted January 10, 2015 Hi Steve, the gearbox drain plug usually has a square head. If the hex head bolt works then leave it. Roger Roger, You and your TR4s!! Most if not all later boxes have a magnetic drain plug which has the hex head and parallel thread as shown in the photo. So, it looks fine Steve. You may find that oil leaking from the engine is blown back to the drain plug and then drip off it. Cheers Graeme Quote Link to post Share on other sites
RogerH Posted January 10, 2015 Report Share Posted January 10, 2015 How many times is that that I've spouted the TR4/4A mantra only to find that ST redrew the universe when they made the TR6 - aaarrrggghhhh I shall watch but say nothing from now on. Roger Quote Link to post Share on other sites
Wilfried Posted January 11, 2015 Report Share Posted January 11, 2015 I've also attached a photo of the overdrive sump..... Odrive Sump (2).JPG Looking at this I assume it needs a new gasket....though it could be oil flowing back from the gearbox I suppose? As always, thanks in advance for the input. Steve Hello Steve, I had the same problem with a leak on the overdrive sump. Replacing the gasket does not help. The problem is in the design: You cannot compress the gasket, because the internal ripps on the cover but against the filter! (Remove the gasket and put the cover on: you will see that you cannot close the gap when screwing the cover on!) The remedy is quite simple: grind away about 1mm of the ripps and you are set! Wilfried Quote Link to post Share on other sites
Percy TR6 Posted January 12, 2015 Author Report Share Posted January 12, 2015 What fun this is turning out to be! Having tried several ways of removing the sump drain plug (sockets, spanners, mole grips etc) without any success I have now arranged for someone to come and weld a hex nut onto the rapidly rounding square head and see if that works. All part of the learning curve! Steve Quote Link to post Share on other sites
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