jogger321 Posted May 3, 2018 Report Share Posted May 3, 2018 Not wishing to hijack other folks threads.... Well the overdrive on my 71 TR6 worked fine....but that was 28 years ago!!! Fast forward car is back on the road after extensive refurb and still owned by me! The overdrive works fine when the car is cold but stops altogether working when it gets hot...Move the switch on the stalk by the steering wheel and nothing happening... When cold ...good click coming from relay inside engine bay and clunk from solenoid underneath gearbox cover (when ignition switched on and car put in 4th & overdrive engaged) When hot ......good click coming from relay inside engine bay and much smaller clunk/almost a click from solenoid underneath gearbox cover (when ignition switched on and car put in 4th & overdrive engaged) It does sound solenoid related but if anybody has had the same problem what should my next steps be please? Quote Link to post Share on other sites
RogerH Posted May 3, 2018 Report Share Posted May 3, 2018 Hi Jogger, firstly make sure all the connection are in good order - although the cold working suggests they are. Have you got a hot air gun. If so, with a cold solenoid apply the warm air to get the solenoid up to 'non' working temp and try to select OD. It could also be the relay in the engine bay - contact going high resistance when warm/hot. Again get the OD hot so it is not working and then apply 12V direct from the battery to the solenoid Roger Quote Link to post Share on other sites
Mike C Posted May 3, 2018 Report Share Posted May 3, 2018 You're probably going to have to remove the H frame and tunnel to get much further. I'd do this and check the wiring above the gearbox - a connection to the wiring of selector switches may be loose and increasing resistance when it gets hot. Having the tunnel off will make Roger's suggested tests above easier if it's not a simple loose connection. Quote Link to post Share on other sites
jogger321 Posted May 3, 2018 Author Report Share Posted May 3, 2018 Ok thanks...All good advice and I will do these and report back.... Quick question (last time I took it off was 29 years ago when I replaced the clutch!) Do you have to get underneath the car to take off the H Frame/ gear box cover or can it all be done from inside the cockpit? Quote Link to post Share on other sites
RogerH Posted May 3, 2018 Report Share Posted May 3, 2018 Hi Jogger, all from inside. Seats out 'H' support and knobs/switches Carpets Tunnel Oh what joy Roger Quote Link to post Share on other sites
Waldi Posted May 3, 2018 Report Share Posted May 3, 2018 And check coil temperature by hand. If very hot, it does stay on the high current (first) travel. This nay also affect the relay/wiring. Waldi Quote Link to post Share on other sites
elclem1 Posted May 4, 2018 Report Share Posted May 4, 2018 A or j type? A type has a relay j type doesn’t. Quote Link to post Share on other sites
peejay4A Posted May 4, 2018 Report Share Posted May 4, 2018 71 will be A type if it is an original fit. Quote Link to post Share on other sites
lightningburns Posted May 4, 2018 Report Share Posted May 4, 2018 Hi Jogger, I think most of the above covers it. The fact that you hear a strong click from the relay even when hot, would indicate that the overdrive switch and interlock switches are all ok, it's a very low current circuit on the initialisation side of the relay. If you were really keen although I don't see much point you could remove the yellow green from W2 terminal on the relay and put an eth on the relay terminal and see if the solenoid pulls in properly. As already advised you could try putting 12V on the solenoid this can be done by pulling off the Yellow purple wire off the relay terminal C2 and putting the 12v onto the yellow purple wire (it will spark though). If the solenoid pulls in from here then it would appear as if the relay is faulty. (WIRE COLOURS TAKEN FROM '71 TR6 DIAG) All this can be done from under the bonnet. This would then leave the wire from the relay to the solenoid which could be high resistance. You can sometimes reach the last connection to the solenoid from underneath the car, if you can that would be the last electrical point to apply 12v to the solenoid. Having said all that, my guess would be the solenoid itself is faulty, I do not know if you can remove it from underneath the car, I am sure others can advise, if not it looks like tunnel off. Regards, John Quote Link to post Share on other sites
jogger321 Posted May 5, 2018 Author Report Share Posted May 5, 2018 Thanks to everyone that responded... I've been out in the car today to take advantage of the nice weather rather than working on it...I've enjoyed my drive but you realise how much the overdrive improves the enjoyment I will report back once i've fixed it what the problem was! Quote Link to post Share on other sites
bluebob Posted May 6, 2018 Report Share Posted May 6, 2018 Hi Jogger worth checking connectors at the tunnel as a common fault can be those of us who have the dip switch next the the wires that come through the tunnel can get knocked with your foot when operating the dip switch which can also cause o/d to cut in/out for reason just mentioned hope this helps? Bluebob Quote Link to post Share on other sites
jogger321 Posted May 25, 2018 Author Report Share Posted May 25, 2018 Head scratching time! + still not fixed! Took the gearbox tunnel off to expose the solenoid... Indeed when the car is cold the solenoid moves properly and its plunger moves in and out with a "Click" and moves the arm it is attached to. I even tested the feed to the solenoid with a multimetre and got 12 V (with engine switched off) when the overdrive switch on the steering was moved to on and no volts when switched off (have I got that the right way around?) Started the car and took it for a drive with gearbox tunnel off (watch your self if you do this as rotating prop shaft exposed) Overdrive not working at all now and Solenoid plunger not moving or only just trying to move...doing this is 2,3 & 4 same thing ...So clever cloggs removes the solenoid...Its a bit dirty and rusty and so I decide to buy a new one Before fitting it I have a feel of the overdrive operating arm that it moves and this feel ok to me...bit of resistance (a spring) but up and down by hand ok and nothing to stop the solenoid moving it properly I fitted the new solenoid yesterday and Grrrrrrr the problem is still there with exactly the same symptoms This says to me its wiring and definitely heat related because if you test it cold the solenoid operates fine with either the old one or new one fitted... Start the car and very quickly the solenoid stops working Where do I start? I did do a quick clean of the terminals that go to the wiring around the overdrive.... There are switches on the overdrive unit itself...Interlock switches??? Could it be these when getting hot are causing the problem? How do I test them, can they be removed/repaired/replaced easily? Any thoughts as how to progress on this one as a TR6 without overdrive is definately not a pleasant to drive as one with :-) Quote Link to post Share on other sites
Hamish Posted May 25, 2018 Report Share Posted May 25, 2018 (edited) Have you checked the relay ?! My tr3a with a TR6 a type OD intermittently stopped working then failed altogether. The solonoid worked with a test direct feed and the relay was clicking away could hear it and feel it when touched. I dont do electricery but Help on here ended up with me changing the relay The least expensive and easiest to get to in a test fix attempt. Result all sorted. H Edited May 25, 2018 by Hamish Quote Link to post Share on other sites
BlueTR3A-5EKT Posted May 25, 2018 Report Share Posted May 25, 2018 (edited) Have you checked the relay ?! My tr3a with a TR6 a type OD intermittently stopped working then failed altogether. The solonoid worked with a test direct feed and the relay was clicking away could hear it and feel it when touched. I dont do electricery but Help on here ended up with me changing the relay The least expensive and easiest to get to in a test fix attempt. Result all sorted. H Just had this problem on two of our family TRs. Both fitted with A type overdrive. Car 1/ The relay clicked but no solenoid clonk - no overdrive operation at all. Car 2/ Intermittent overdrive operation when cold with occasional sound from both relay and solenoid when stopped. 1/ Tested circuits through relay in all gears to check inhibit switch function- 1/ Circuit through relay fine in 2/3/4. - Traced wiring down to solenoid found melted insulation on the wire feed to the solenoid. Caused by the plunger being stuck to the rubber buffer it sits on when deactivated - oil soaked Solution. 1/ Renew the burnt out solenoid. - replaced rubber buffer with metal screw to act as a lower limit stop. 2/ Tested circuits through relay in all gears to check inhibit switch function- 2/ Had low or no voltage flow through contact circuit in 2/3/4. Solution 2/ Remove and Strip relay, clean contact points, rebuild & refit. Both overdrives working fine now. Peter W Edited May 25, 2018 by BlueTR3A-5EKT Quote Link to post Share on other sites
Mike C Posted May 25, 2018 Report Share Posted May 25, 2018 I'd check the voltage at the solenoid when its hot and not working . If it's low measure at any available points along the wiring until you get 12V. Quote Link to post Share on other sites
lightningburns Posted May 25, 2018 Report Share Posted May 25, 2018 Hi Jogger, Yes you can be lucky and find an electrical fault, but you should really approach it in a logical way. All the necessary info has already been suggested. However now you have got the tunnel off why not get it hot again and failing to pull in the solenoid. With it just stationary engine off, disconnect the wire from the solenoid, connect a jump lead from the battery positive to the lead from the solenoid (it will spark) does the solenoid pull in correctly, if it doesn't then the solenoid or overdrive unit appears to be at fault. If it does pull in it points to electrical faults, info has already been provided on how to isolate the fault. Once you have done the basic test outlined above quickly put back the wiring for the solenoid, select 4th gear turn on the ignition and operate the overdrive switch to make sure the solenoid is still failing, that will ensure that the previous test is valid. It is essential you do this otherwise you can go round in circles. Regards, John Quote Link to post Share on other sites
Murty Posted May 25, 2018 Report Share Posted May 25, 2018 Hi, I had a similar problem o/d worked when cold not when hot. I didn't do as much with the solenoid as you did as I could like you hear it hot and cold. mine turned out to be failing accumulator that was unable to provide sufficient pressure with hot (less viscous) oil. I fitted an exchange o/d and it all works fine. Quick word of warning I was at Overdrive Spares when the old o/d was opened and since the clutch had been trying to engage without enough pressure the clutch lining had broken. O/D Spares were helpful I was trying to solve this may be worth giving them a ring. One more thought to confirm if it is the solenoid wiring why not try getting it all hot and remove the solenoid form o/d an see it the plunger moves when you engage the o/d. I found the info on this page really helpful ( Dave Quote Link to post Share on other sites
Murty Posted May 25, 2018 Report Share Posted May 25, 2018 sorry link is http://www.buckeyetriumphs.org/technical/AOD/AOD5/AOD5.htm Quote Link to post Share on other sites
jogger321 Posted August 22, 2018 Author Report Share Posted August 22, 2018 (edited) I hate it when you read a thread all the way because you have a similar problem and you get to the end and the original poster hasn't come back whether they managed to fix it! Anyway I'm back ...and it's fixed!! (I've left it a few weeks to make sure it seems to be a lasting fix and it seems to be)... Hope my experience helps somebody some time in the future So in the end the solenoid was was replaced ...and it only worked intermittently ...when it was cold I checked the solenoid adjustment/operating arm on the overdrive using a drill and it was spot on and did not attempt to adjust it. Relay replaced relay...same problem Put Voltmeter on new Solenoid whilst being used....12 Volts showing Isolated circuit to take enabler/inhibitor switches out of the circuit (GO EXTREMELY CAREFUL IF YOU DO THIS AS PUTTING THE CAR IN REVERSE AND MOVING EVER SO SLIGHTLY WILL WRECK THE OVERDRIVE)......This didn't fix it either Remove Solenoid altogether and tie a piece of string to the operating arm on the overdrive that the solenoid moves Find a PRIVATE road and taking extreme care with the exposed prop shaft (it will remove your fingers if you catch them or strangle you if a scarf is caught in it etc) take the car for a drive and using the string attempt to operate the overdrive...or if you have a friendly obliging passenger get them to do it so you can keep both hands on the wheel.... When I did this I found the overdrive was working perfectly!....Engaging and disengaging smoothly ....So my conclusion was it was still something electrical....but what?? The overdrive gearbox wiring loom looked like it has seen better days...(I had already cleaned all the terminals) so in the end I purchased a replacement one from Autosparks for arounf 25 pounds. What showed up was a much higher quality product than the original. I fitted it and took the car for a drive.....Full working ultra smooth overdrive in and out So it was the wiring harness in the end although I think the original solenoid was not helping as I noticed the new Solenoid has far more "pull" than the original "worn"? I'm not great on electrics to be honest and dont really understand why I was getting 12V at the solenoid end with the old loom and old solenoid/new solenoid and it stopped working when hot...I can only assume that its something to do with the old wiring in the loom being degraded after being nearly 50 years old and high resistance developing when hot.?? Anyway I'm delighted I managed to fix it on the end and thanks for all your suggestions along the way. Edited August 22, 2018 by jogger321 Quote Link to post Share on other sites
Hamish Posted August 22, 2018 Report Share Posted August 22, 2018 Well done ???? Its great when you fix something that isnt straightforward or high in ones knowledge bank. This forum is great for advice and the confidence it gives. H Quote Link to post Share on other sites
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