Mat Posted June 30, 2018 Report Share Posted June 30, 2018 Hi I'm having a few problems with my overdrive (D type mk3 GT6). it did not want to cut in until you drove it for about 15 - 20 mins. then it work fine for the rest of the day. I thought it might be a little low on gearbox oil causing this problem, so the other day I took off the cover and it took around 100ml.(I also found one of the overdrive solenoid wires was slightly shorting on the gearbox so fixed that also) I put it back together, now it works right away but sometimes it wont cut in at all (if I flick the switch a few times I might cut in eventually) sometimes it cuts in, then out, then in again (all in about 5 seconds) then occasionally it just drops out for no reason as you are driving along especially at speed (60 - 70) it is sat at 3,000 revs, then it jumps to about 4,000 revs. Anyone have any ideas where to start with this one? It usually only does short runs (about 10 - 15 miles) does it need a good fast run? or is it more likely to be the relay? (i try moving the gear lever a bit, but that makes no difference, so I think the switches on the gearbox are ok) Many thanks in advance. Matt Link to comment Share on other sites More sharing options...
Anglefire Posted June 30, 2018 Report Share Posted June 30, 2018 It does sound electrical - I would think a dodgy switch or perhaps poor connection. But I say with with no real basis! Link to comment Share on other sites More sharing options...
ShaunW Posted June 30, 2018 Report Share Posted June 30, 2018 Could be a faulty switch on your gearstick. Mine failed gradually. I also had a situation where the continuity tested OK throughout the circuit but it still didn't work. I remade a scruffy looking connection half way down the dark green +ve that comes in from the engine bay and it worked. Looks like it was connected enough to read zero ohms but was failing when it needed a burst of 20amps to kick the solenoid. Link to comment Share on other sites More sharing options...
Clive Posted July 1, 2018 Report Share Posted July 1, 2018 The wiring down the gearstick is notorious for breaking. In fact the conductors can fracture inside the OK looking insulation, causing intermittent make/break problems. It 99% likely to be wiring, so go though it all. Sadly it probably means tunnel again, but you will be getting to be an expert! Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 1, 2018 Report Share Posted July 1, 2018 Could also be the solenoid end switch failing when the sol pulls in it trips a small cut out switch in the end under the rubber cover most are not diy repairable, do check the lever under the plate is aligning its hole withnthe case when pulled in easy to test the feed wiring add a small bulb into the cabin so it lit when IN and driving The lever hole alingment can be adjusted to give a little more travel it has to lift a small valve under the cap nut on the top of the case Do eliminate any chafed or heated wires uo the gear stick and phyically check the inhibitor switch on the front of the remote Small adjustments here work wonders Pete Link to comment Share on other sites More sharing options...
NonMember Posted July 1, 2018 Report Share Posted July 1, 2018 If you've had intermittent shorting, did you replace the whole wire or just tape it up? The symptoms sound electrical and if you've had that sort of problem for any length of time I'd be suspicious of the whole circuit. Link to comment Share on other sites More sharing options...
Guest Posted July 1, 2018 Report Share Posted July 1, 2018 Matt, Prior to the Vitesse g/box coming out, earlier in the year, I checked the wiring leading up to the gearstick-switch; the photos say it all !! The O/D engaged and disengaged without issue but it was only a matter of time before an electrical issue occurred with the wire sleeve breaking and poor connections. One of the main problems with the wires going in to the gearstick hollow is that no protective sleeving follows it up to the switch. This is a short cut by many owners and a poor one to say the least for obvious reasons. Yes the gearstick channel is slim but if you use Thinwall wire and heat shrink protective conduit it fits perfectly. Whilst a good friend overhauled my transmission I made up a complete brand new loom to fit on the units return; it's only a few hours work and certainly worth doing. Additionally I would certainly recommend all of the wires to be shrouded in a protective covering not only to deal with wear & tear but also to protect from the heat generated within the tunnel area. Regards. Richard. Link to comment Share on other sites More sharing options...
JohnD Posted July 1, 2018 Report Share Posted July 1, 2018 OR, Forget the gearknob switch and fit one to the steering wheel. Length of 'curley-whirley' cable, a press-on-press-off button and a warning light if you wish. (I've abandoned the lap timer!) JOhn Link to comment Share on other sites More sharing options...
Mat Posted July 1, 2018 Author Report Share Posted July 1, 2018 Thanks for all the replies, I'm pleased to hear everyone thinks it is electrical ( I can replace the whole lot fairly easily & cheaply if necessary) it did have a new switch and lever wire about 12 months & about 1,500 miles ago, when I rebuilt the car (Not that is means it is still ok) are some of the switches out there (like other car electrics) not very good? Can the relay fail intermittently? It is original and out in the weather a few years before my ownership Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 1, 2018 Report Share Posted July 1, 2018 relays can obviuosly decide to play up just like any other part the inhibitor switches can fill with green stuff and make erratic contact, some can be prised open and cleaned up as said stick a small test bulb in the solenoid feed and see if it goes on and off with the misbehaving,is the power supply is constant but the od drops out then look at replacing the solenoid...thats fun PETE Link to comment Share on other sites More sharing options...
Mat Posted July 4, 2018 Author Report Share Posted July 4, 2018 On 7/1/2018 at 3:35 PM, Mat said: it did have a new switch and lever wire about 12 months & about 1,500 miles ago, when I rebuilt the car (Not that is means it is still ok) are some of the switches out there (like other car electrics) not very good? I can answer my own question! YES there are some bad quality switches!!? The 12 month old Switch is faulty (marked with the Lucas logo) plus the 12 month old the gearstick wire is chuffed and worn!! Everything else with the overdrive is 47 years old and working fine! Done a temporary wire and switch (with light) that's in front of the gear lever. Many thanks to everyone who helped Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 5, 2018 Report Share Posted July 5, 2018 If you have to rewire the gearstick get some silicon sleeved wire its far better and mor flexible in hot conditions Or fit a stalk on the column or dash and save the hassle Pete Link to comment Share on other sites More sharing options...
Mat Posted July 5, 2018 Author Report Share Posted July 5, 2018 3 hours ago, Pete Lewis said: If you have to rewire the gearstick get some silicon sleeved wire its far better and mor flexible in hot conditions Or fit a stalk on the column or dash and save the hassle Pete Thanks for the advice, I've ordered one from Rimmers (as well as a new switch) looking at the photo of the cable, it seems better as it looks to have a separate (silicone?) sleeve that should allow for more movement, Hopefully! Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 5, 2018 Report Share Posted July 5, 2018 you will see the terminals for the switch are round with a slot in this has to locate on the blade in the switch , just in case this is not obvious keep plenty of spare loose cable where it exits the stick so theres easy movment without cable stress Pete Link to comment Share on other sites More sharing options...
NonMember Posted July 5, 2018 Report Share Posted July 5, 2018 That's definitely better than the table light mains cable that a lot of these are made from. Just make sure, when you fit it, that the sleeve sits properly inside the gear stick so that it protects the blue and brown wires at both ends. Link to comment Share on other sites More sharing options...
Guppy916 Posted August 15, 2018 Report Share Posted August 15, 2018 I have popped the steering wheel off made a new brass ring for the overdrive and now it works off the left button on the steering wheel and the horn on the other button, purchased a new horn contact brush Rimmer's part number 142534, time consuming but worth it, (only two buttons are used) this all works through a relay so no currant draw through the switch, and no wires showing Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 15, 2018 Report Share Posted August 15, 2018 nifty, good wheel for knees clearance, everyone laughs at Austin Allegro with a squared off rim but ...it works every one does it these days Pete Link to comment Share on other sites More sharing options...
Colin Lindsay Posted August 16, 2018 Report Share Posted August 16, 2018 You could always turn one upside down and talk to it as you drive..... Doctor! Me tablets have run out again! The steering wheel is answering back! 1 Link to comment Share on other sites More sharing options...
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