euan douglas Posted July 27, 2016 Report Share Posted July 27, 2016 My overdrive has ceased to function and as I can hear the relay clicking in and out as it should I suppose the issue could be with the solenoid. O/D had been taking a few seconds to engage when selected so this may mean it has now given up or is a solenoid failure a rare occurrence? Is it possible for the relay to work but there be an electrical fault further downstream? I've read some posts on the O/D filter becoming clogged so that might be another cause? Lastly (for now!) does the O/D unit have a separate oil fill or is it fed from the gearbox as I also see that low oil levels can be a cause? Any thoughts on the sequence of troubleshooting to be followed would be appreciated and sorry if all this has been addressed elsewhere recently. Euan Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 27, 2016 Report Share Posted July 27, 2016 Check oil level there is only one filler on the gearbox the OD collects its oil from the geabox, so its important the box is on level ground and filled till it trickles back out the filler , . OD wiring up the gear stick is a very common failure due to heat and chafing solenoods can fail if its D type fitted on drivers side RH. its worth checking its not gone rusty insde making the armature slow , the armature plunger operates a switch at the end of its travel to cut the pull in 10amp coil down to a holding coil of 0.5amp the filter can get some real nasty gooey stuff inside its fitted under the plate on the lh side , need to pull the filter and the 3 magnetic rings to clean it on the solenoid side there is a cover plate , under in a lever pulled by the solenoid, it has ahole in which when energised should align with a hole in the case behind the lever the inhi itor switches can get full of green mould , you can uncrimp them and clean out the simple terminals inside if all this reveals little in the top ofnthe case is a hex headed cap screw , inside is a ball spring and small spool valve, this has a tiny hole down its centre and this can block , a lenght of fuse wire wil clear it dont loose the ball and spring this all may sound tedious but its pretty easy, apart from removing the solenoid lower screw can be a fiddle pete Link to comment Share on other sites More sharing options...
Waynebaby Posted July 27, 2016 Report Share Posted July 27, 2016 Euan, Before you start taking out the gearbox tunnel (never a nice job) just double check that the relay is definitely energising the solenoid circuit. Disconnect the yellow/purple cable from terminal C1 on the O/D relay and put a voltmeter or a test bulb between the terminal and earth. You will get a voltage at this terminal if the relay is working correctly when the O/D switch is moved to the "in" position. If this shows the relay is working OK the next job is to get the gearbox tunnel cover out of the car and check the continuity of that yellow/purple cable down to the solenoid itself. If that is OK then take the small cover off the O/D unit on the drivers side (the one with the Laycock writing in blue and silver) and see if the little brass lever beneath moves when the solenoid is energised. If there is no movement then you almost certainly need a new solenoid. If you do need a new solenoid then you will also require thin, freakishly long and double jointed fingers, screwdrivers with flexible drives and the patience of Job to change it. There is no easy way that I am aware of to do this task I'm afraid. good luck Wayne Link to comment Share on other sites More sharing options...
Waynebaby Posted July 27, 2016 Report Share Posted July 27, 2016 Damn. Pete beat me to it! Link to comment Share on other sites More sharing options...
dougbgt6 Posted July 27, 2016 Report Share Posted July 27, 2016 You godda be quick to beat old pom pom slippers! Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 27, 2016 Report Share Posted July 27, 2016 Just wonder if I could get a couple of jetex motors on them slippers?? should liven up the old knee s a bit come on Doug you must remember them if you can undo the rear mount you can improve accees with the long fingers, mixture of drive bars and flexibles to get the bottom screw to submit by jacking up the tail of the gearbox a little Link to comment Share on other sites More sharing options...
JohnD Posted July 27, 2016 Report Share Posted July 27, 2016 See Canley Classic's pages on Overdrives and troubleshooting. This is the D-Type, there is another on J-type. http://www.canleyclassics.com/technical-archive/the-d-type-overdrive JOhn Link to comment Share on other sites More sharing options...
Waynebaby Posted July 28, 2016 Report Share Posted July 28, 2016 Just to answer Euan's final question, the gearbox oil and the O/D oil are one and the same. Wayne Link to comment Share on other sites More sharing options...
dougbgt6 Posted July 28, 2016 Report Share Posted July 28, 2016 ***warning** Thread drift. Yes, Jetex engines with solid fuel pellets! Always wanted one. You will, of course, have to fit heat shields on the pom poms, to avoid disaster! http://www.ebay.co.uk/itm/Jetex-Model-Ariplane-motor-and-Charges-tin-/172282698297?hash=item281cd95a39:g:u3wAAOSwTZ1XlO2x Link to comment Share on other sites More sharing options...
euan douglas Posted July 28, 2016 Author Report Share Posted July 28, 2016 Back to reality! Thanks everyone for the trouble shooting guide - I shall investigate further. On another topic I posted recently, that of fuel and temp gauge failure/voltage regulator, I see what is meant by the continuity across the fuse blades at one end, what a strange setup. I removed the top fuse, cleaned everything up and made a better connection for the fuse - all seems well so far, so hopefully that is that sorted ? Though a poor connection may be due to the fact that some of the plastic pillars between the fuses are missing thus allowing the blades to wobble about somewhat. I suppose if push comes to shove a new fuse box can be fitted easily(?) even though it has the loom passing through it, just put a cut in the plastic and slip it over the loom??? Sorry for jumping topics. Euan Link to comment Share on other sites More sharing options...
dougbgt6 Posted July 28, 2016 Report Share Posted July 28, 2016 Euan, 3 fuses for the GT6 is totally inadequate, Triumph wouldn't get away with it today! You may or may not know that the headlights have NO fuses, at all! The wire comes from the battery to the light switch and then on to the headlights, Worse still ALL the current for the lights goes through the switch. The switch corrodes and you've got a voltage drop, dim lights and a fire risk. Many here have fitted relays and a new modern fuse box with many more fuse options. I have a 12 way one, sitting in the garage waiting to go, but I'm wondering if 12 is enough!. There is plenty of room to fit it. It's just deciding how far you want to go, it's a big job fusing everything individually. For the present I installed a part wiring loom I got of Ebay from China. It was incredibly cheap and easy to fit. It incorporates relays and fuses for the lights. http://www.ebay.co.uk/itm/H4-H4-Headlight-Headlamp-Black-Booster-Wire-Harness-Cable-SAYG-AI3G-/152016433561?hash=item2364e2b199 Doug Link to comment Share on other sites More sharing options...
euan douglas Posted July 28, 2016 Author Report Share Posted July 28, 2016 Thanks for that Doug, food for thought indeed and another potential job! Wayne On the Haynes wiring diagram the yellow/purple wire goes to C2 and the one to C1 is brown, but on the car Y/P is to C1 so I guess that is the terminal to test to earth? Also in Haynes terminal C2 is shown going to the solenoid whereas C1 goes to ignition switch No1. So basically I'm saying is the Haynes diagram wrong? Confusion reigns! Euan Link to comment Share on other sites More sharing options...
Waynebaby Posted July 28, 2016 Report Share Posted July 28, 2016 Hi Euan, Please accept my apologies but on checking on my car I was mistaken about the terminal which feeds the solenoid (I should put on my reading glasses more often) The correct terminal which energises the solenoid via the Y/P is C2, which is the one in the centre of the relay and C1 should have a brown wire which becomes live when the ignition is switched on. In other words, the Haynes manual is correct (so I'm puzzled by the Y/P wire being attached to C1 on your car) Sorry for the confusion. Wayne Link to comment Share on other sites More sharing options...
euan douglas Posted July 28, 2016 Author Report Share Posted July 28, 2016 Wayne Right, I had another look at mine - C1 has the Y/P wire going to it and C2 has the brown wire, the W1 and W2 terminals are white and Y/G respectively. So on mine the brown and Y/P wires are the opposite from your's! However the O/D has been working fine up 'til yesterday and I can hear the relay clicking in and out as I select O/D on the gearstick switch - but still no O/D! I wonder does it matter if C1 and C2 are swapped as the relay internals in Haynes (page 123) look as though it might not? In my case to test it therefore I should disconnect the Y/P wire from C1 (not C2) and check for a current to earth? All very confusing! Euan Link to comment Share on other sites More sharing options...
Waynebaby Posted July 28, 2016 Report Share Posted July 28, 2016 Hi Euan, I agree with you that unless the relay has some particular need for polarity the reversal of the connections to the C1 and C2 terminals shouldn't make any odds to how it works, in which case checking for a current to earth from C1 (instead of C2) should still tell you if the relay is energising the feed to the O/D solenoid. Fingers crossed Wayne Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 28, 2016 Report Share Posted July 28, 2016 C1 -C2 swapping only reverses the polarity of the current thro' the pull in coil not overlly important on a small relay Pete Link to comment Share on other sites More sharing options...
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