Darren Sharp Posted August 23, 2014 Share Posted August 23, 2014 Hi All I am having a massive O/D headache with OlaF my Mk 2 2500 Saloon. The Symptoms were a gradual loss of O/D over about 4 months with occasional trouble free eureka drives when it worked . I tried all the usual remedies involving Oil level and electrical gremlins but I have continuity at all the joins and everything is coming up as normal on the voltmeter. At this point I decided to check the filter and the oil was sieved out to check for metal . It was spotless so it was cleaned up and returned to its proper place. Despite this I persuaded myself that the Solenoid was most likely the problem and bit the bullet .... Wrong ! In desperation I rigged up a direct supply via a separate switch and hey presto! Instant overdrive whilst being carefully driven round the block. It was about now that I noticed that when the jury rigged connection was manually removed with the system live (Ignition on. O/D Switch on in 3rd or fourth) that there was an almighty spark ( it was dark by now) and I could also hear the solenoid engage. This does not happen when the system is returned to its correct wiring although the meter shows the same voltage at the solenoid as when its wired direct to live. Further investigation of the torturous wiring with most of the centre console and big rubber bung removed revealed that if I bypassed the inhibitor on top of the gearbox by removing and joining the wires then I enjoyed the big spark phenomenon again ( It was very dark now ). Am I on the right track please because I will have to drop the cross member to change the Damn switch as I do not have access to a double jointed midget!Thank you Quote Link to comment Share on other sites More sharing options...
bob dunn Posted August 23, 2014 Share Posted August 23, 2014 I put an earth wire on to the solenoid and have seen a few on other cars Quote Link to comment Share on other sites More sharing options...
Clive Posted August 24, 2014 Share Posted August 24, 2014 Not always about voltage, but current. Had several issues when a voltmeter showed 12v but the bulb/whatever wouldn't work. Really frustrating.Looks like a bad connection somewhere, and check the earth wire. Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted August 24, 2014 Share Posted August 24, 2014 UNdoubtedly a high resistance somewhere that is preventing enough current passing.A type or J-type?Is there a relay fitted?If J-type and no relay then it could be just about anything, including the actual contacts of the gearlever switch or inhibitor switch.If there is a relay (J type or A type) and the relay itself pulls in, then it has to be something in the power circuit (not switches just mentioned which are in the relay coil circuit) and could be the relay itself.Nick Quote Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 24, 2014 Share Posted August 24, 2014 its not uncommon for the contacts inside the inhibitor switch to be green and past it, whilst is invisible its worth a check if you can get it out, uncrimp the sa141 base plastic and all will be revealed , you could try to google a double jointed midget ?? on mine it had a mind of its own, that was a jammed lack of use solenoid piston no sparks just did what it wanted with no controll just in out all by its self. just remove the circlip inside the end of the sol and extract the plunger , clean and replace, pete Quote Link to comment Share on other sites More sharing options...
CRAJ Posted August 26, 2014 Share Posted August 26, 2014 I had similar on the estate during the 08 RBRR, I bypassed the lever harness and switch (whilst Dad drove through the highlands) and all was fine. Changed the lever harness and it has been fine ever since.Colin. Quote Link to comment Share on other sites More sharing options...
BlakeJ Posted August 26, 2014 Share Posted August 26, 2014 I have found the swtiches to be absolute rubbish, mine was buggered so i brought a brand new one from rimmer bros. It was getting so hot it was making the gearstick almost too hot to touch!!!! so yea big resistance there. I have my own new wiring harness with relay, changed the swtich and boom, all good. From what i have found with the headaches on mine is 99% of the troubles you will have with O/D are electrical. Quote Link to comment Share on other sites More sharing options...
Greeks Posted August 28, 2014 Share Posted August 28, 2014 I gave up with the original-style switch - too prone to breaking. Got one of these instead:http://www.bighealey.co.uk/content/overdrive-gear-lever-knobIIRC young Bancroft has one too Quote Link to comment Share on other sites More sharing options...
Tim Bancroft Posted August 29, 2014 Share Posted August 29, 2014 Yes, on the GT6, very good is it as well, if a little pricey for just a toggle switch and a lump of alloy.Dave Pearson has an original one, made of nylon, very nice.On the saloon, I have a toggle switch on the column, looking for an original lever as I my old one is fubar. Quote Link to comment Share on other sites More sharing options...
Slimboyfat Posted August 29, 2014 Share Posted August 29, 2014 I used to have one of those aluminium ones in my Vitesse, but it used to get very hot after a long jouney so I ditched it for an original dash mounted type.This is the reason why Abingdon used nylon knobs on the works cars. Quote Link to comment Share on other sites More sharing options...
Tim Bancroft Posted August 29, 2014 Share Posted August 29, 2014 Yes, of course it is important to note that these knobs were first used on BMC rally cars-mainly the Big Healey, and then used on the 2.5Pi world cup rally cars. Quote Link to comment Share on other sites More sharing options...
thescrapman Posted August 29, 2014 Share Posted August 29, 2014 Russell has a very nice aluminium knob in his GT6, courtesy of Chris the previous owner.I still the imprint of it burnt into my left hand from the 2013 HCR... :-(A couple of socks over it would have solved the problem... :-) Quote Link to comment Share on other sites More sharing options...
ferny Posted August 29, 2014 Share Posted August 29, 2014 "Colin, why is there only one of these socks out for washing?""Oh yeah, Russell put it on his knob. It's still in his car so I'll get it back when I see him.""Erm... let him keep it." Quote Link to comment Share on other sites More sharing options...
Radders Posted August 29, 2014 Share Posted August 29, 2014 Greeks wrote:I gave up with the original-style switch - too prone to breaking. Got one of these instead:http://www.bighealey.co.uk/content/overdrive-gear-lever-knobIIRC young Bancroft has one tooI now have one of these on Gertie as well. It should be known though that these wont screw straight on to a Mk1 or Mk2 saloon gearstick. The Mk1 thread is 5/16th UNC, and this gearnob has a 3/8ths UNC thread. I had to find a 3/8 UNC bolt with a long shank and then had it welded onto Gertie's original gearstick. :) Quote Link to comment Share on other sites More sharing options...
nang Posted August 30, 2014 Share Posted August 30, 2014 Also agree with Greeks, never had much success with the original switch. Have replaced them on 2 cars with one in pic. Nice bullet proof Hella switch powering a relay, in turn powering the J type solenoid. No more problems. The S that I'm playing with at present has the original switch, o/d wasn't working when I drove her home but will reserve my judgement until I check the rest of it .This switch works across an ohm meter but terminals were loose on switch.Tony. Quote Link to comment Share on other sites More sharing options...
Greeks Posted August 31, 2014 Share Posted August 31, 2014 Yes, Radders, had to tap it to fit. And also a smear of silicon on the cap stopped it from vibrating.Weird that people get hot knobs, though. Mine stays as cool as a cucumber even on hot Austalian days... and don't just take my word for it, my wife's never complained. :o Quote Link to comment Share on other sites More sharing options...
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