RichT Posted May 2, 2018 Report Share Posted May 2, 2018 Hello. I have a problem with the a type overdrive on my 69 tr6. It keeps blowing fuses every time i try to engage it. It used to work fine but the started to blow fuses whilst engaged. As a result i have replaced everything electrical in the overdrive system including the loom! It is still blowing fuses? Can anyone shed some light on what to check next as i would love to have it working again. Mechanically it still seems to work as it engaged when that little lever on the side was moved. Quote Link to post Share on other sites
Nigel Triumph Posted May 2, 2018 Report Share Posted May 2, 2018 Sounds like the overdrive is engaging correctly on the pull in part of the solenoid then sticking there, rather than moving to the holding coil part of solenoid. From memory, pull in coil takes 10+ amps and holding coil about 2 amps. This can explain burning out, as the solenoid can only take the high pull in coil current briefly. Try adjusting the solenoid push rod. Workshop manual will detail the exact procedure. Nigel Quote Link to post Share on other sites
Austin Branson Posted May 2, 2018 Report Share Posted May 2, 2018 Hello Rich, I am no expert, and you will almost certainly get advice from those that are. My two-pennerth is around the premise that the solenoid uses a lot more current when engaging the overdrive, than it does simply 'holding it in'. In other words, I think your solenoid is trying to engage the overdrive, when in reality it is already engaged. I think it would be worthwhile to re-calibrate the solenoid travel. Do you have a technical manual? If so, there should be a section on how to do this. If you don't, come back to me and I'll see what I have to help. Let us know how you get on. Austin Quote Link to post Share on other sites
Mike C Posted May 2, 2018 Report Share Posted May 2, 2018 I'd check the solenoid coil resistance for a direct short. When you checked the shaft movement was this by hand or by electrically engaging the coil? Quote Link to post Share on other sites
RichT Posted May 4, 2018 Author Report Share Posted May 4, 2018 It was by hand. Quote Link to post Share on other sites
Mike C Posted May 4, 2018 Report Share Posted May 4, 2018 If the shaft moves and its movement is correctly set ( as noted above, this procedure is detailed in the Brown Book and from memory you need to get access to both sided of the OD to check it) then its probably electrical. Check the resistance of the solenoid coils or use an ammeter to check the coil current consumption-it should initially be 15-20 amps then drop back to 2 amps. Quote Link to post Share on other sites
Litespud Posted May 11, 2018 Report Share Posted May 11, 2018 If it used to work fine, and then stopped working fine, this sounds like the solenoid to me. When you flip the O/D switch, the solenoid momentarily draws ~20 amps for the "pull up" part of the operation. The solenoid "piston" hits a switch at the top of its travel that switches to the "hold up" circuit, which draws ~1 amp. The initial pull up is so brief that you can't see it on a digital meter - the meter goes straight to 1 amp. If the switch is dirty or otherwise malfunctioning, the solenoid will continue to draw 20 amps, to the detriment of the supply circuitry, although I would think that the solenoid coil itself might burn out from a sustained 20 amps. Not sure how to test - maybe use a 12 volt supply, with a meter in the circuit, connect the solenoid up and see what the sustained draw is. If it's any more than 1-2 amps, time for a new solenoid Quote Link to post Share on other sites
RogerH Posted May 11, 2018 Report Share Posted May 11, 2018 Hi Litespud, if the internal switch in the OD solenoid has dirty or none functioning contacts then you often get a chattering racket from the solenoid. The 'pull in' coils draw 20 amps. The plunger hits the switch and the 'pull in' is cut off. But there is no 'hold in' coil. So the 'pull in' coil comes back on line. And so it continues chattering away. I'm sure there are other faults where there is no chattering. Roger Quote Link to post Share on other sites
RichT Posted May 11, 2018 Author Report Share Posted May 11, 2018 Got it adjusted and working correctly. Have driven approx 400 miles with it functioning correctly and now its blowing fuses again????? Still got a 200+mile journey home to do and no tools to work on it. Quote Link to post Share on other sites
Rem18 Posted May 11, 2018 Report Share Posted May 11, 2018 (edited) Roger is right. There is a contact I once tried to overhaul (closing gap and stuff) but they get weak as if the coils get weaker. I see to recall a replacement is not terrible cost?? Edited May 11, 2018 by Rem18 Quote Link to post Share on other sites
Mike C Posted May 11, 2018 Report Share Posted May 11, 2018 This is a comprehensive article on the A type overdrive that I've never seen before. https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&cad=rja&uact=8&ved=0ahUKEwjO8KzOxv3aAhXGipQKHUfMC14QFghSMAg&url=http%3A%2F%2Fwww.thorden.dk%2FTeknik%2FA%2520Type%2520Overdrive.pdf&usg=AOvVaw1YtaSbYgN5FX974bZ6jzSA Assuming the solenoid has been mechanically set correctly, you might like to try the electrical tests at the end. I hate unnecessarily changing to new parts , unless NOS, but Rimmers do have A type solenoids listed for 30 pounds including tax Quote Link to post Share on other sites
Litespud Posted May 11, 2018 Report Share Posted May 11, 2018 Hi Roger - that wasn't my experience. I "bench tested" my solenoid with a 12 volt source when I was overhauling the overdrive. Once I connected the current, the piston shot up and the solenoid just sat there, drawing ~1 amp. There was no noise or chattering Quote Link to post Share on other sites
dingle Posted May 12, 2018 Report Share Posted May 12, 2018 (edited) This is a comprehensive article on the A type overdrive that I've never seen before. https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&cad=rja&uact=8&ved=0ahUKEwjO8KzOxv3aAhXGipQKHUfMC14QFghSMAg&url=http%3A%2F%2Fwww.thorden.dk%2FTeknik%2FA%2520Type%2520Overdrive.pdf&usg=AOvVaw1YtaSbYgN5FX974bZ6jzSA Assuming the solenoid has been mechanically set correctly, you might like to try the electrical tests at the end. I hate unnecessarily changing to new parts , unless NOS, but Rimmers do have A type solenoids listed for 30 pounds including tax This is a comprehensive article on the A type overdrive that I've never seen before. https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&cad=rja&uact=8&ved=0ahUKEwjO8KzOxv3aAhXGipQKHUfMC14QFghSMAg&url=http%3A%2F%2Fwww.thorden.dk%2FTeknik%2FA%2520Type%2520Overdrive.pdf&usg=AOvVaw1YtaSbYgN5FX974bZ6jzSA Assuming the solenoid has been mechanically set correctly, you might like to try the electrical tests at the end. I hate unnecessarily changing to new parts , unless NOS, but Rimmers do have A type solenoids listed for 30 pounds including tax This is a comprehensive article on the A type overdrive that I've never seen before. https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&cad=rja&uact=8&ved=0ahUKEwjO8KzOxv3aAhXGipQKHUfMC14QFghSMAg&url=http%3A%2F%2Fwww.thorden.dk%2FTeknik%2FA%2520Type%2520Overdrive.pdf&usg=AOvVaw1YtaSbYgN5FX974bZ6jzSA Assuming the solenoid has been mechanically set correctly, you might like to try the electrical tests at the end. I hate unnecessarily changing to new parts , unless NOS, but Rimmers do have A type solenoids listed for 30 pounds including tax The articles are from the Buckeye site. Berry Edited May 12, 2018 by dingle Quote Link to post Share on other sites
jogger321 Posted May 12, 2018 Report Share Posted May 12, 2018 Any hints when fitting a replacement solenoid on an A type on getting the adjustment correct? Quote Link to post Share on other sites
stuart Posted May 12, 2018 Report Share Posted May 12, 2018 Hi Roger - that wasn't my experience. I "bench tested" my solenoid with a 12 volt source when I was overhauling the overdrive. Once I connected the current, the piston shot up and the solenoid just sat there, drawing ~1 amp. There was no noise or chattering Exactly what it should do but if the contacts at the top of the solenoid are dirty or damaged then the hold in coil transfer wont take place so the rod will slip down and the pull in coil will take over again and so on hence giving the chattering effect and ending with the solenoid burning out. Stuart. Quote Link to post Share on other sites
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