moosetvr Posted January 17, 2008 Share Posted January 17, 2008 Hello all,I have been having an issue with the overdrive system on my 1971 2.5PI. Overdrive had been working perfectly until a few weeks ago.When you engage the overdrive switch, overdrive engages, then after a few seconds it starts cutting in and out of overdrive by itself and you can hear a electrical crackling noise coming from around the relay are in the passenger footwell. Then when the car is warmer it stops engaging completelyChanged the relay, still the same. Have tested the switch all okay, and with ignition on and car in 4th and overdrive you can hear the relay click when you operate the overdrive switch.Any ideas or pointers before I start delving some more ??Thanks Darren. Link to comment Share on other sites More sharing options...
steadyg Posted January 17, 2008 Share Posted January 17, 2008 Electrical. Test all the wiring for breakages.Garry Link to comment Share on other sites More sharing options...
moosetvr Posted January 17, 2008 Author Share Posted January 17, 2008 I have never played with an A type overdrive before, any known weak electrical areas ie inhibitor switch, gearbox wiring etc. Link to comment Share on other sites More sharing options...
AlanChatterton Posted January 17, 2008 Share Posted January 17, 2008 I had the same issue on my 71 PI. Its the Overdrive relay (mounted by the flasher unit next to the fuse box, behind the passengers side shelf!)Either,a) The relay in playing up, replace.or more likelyb) Bit if wiring getting suspect, loose connection etc.It is basically wired like a normal relay. Power in, earth (check the earth!) then the switching side of it goes via the isolator on the top of the gearbox and the gear lever switch.The load side just goes to the solenoid at the bottom of the gearbox then to earth.Get your tester out and check all connections and wires.........or maybe change the relay. Link to comment Share on other sites More sharing options...
Nick Jones Posted January 17, 2008 Share Posted January 17, 2008 Is A type like D type with twin windings on the coil? (high current coil to engage switching to lower current holding coil when fully home) If so it could be that the solenoid is not pulling all the way in and the relay is objecting to sustained high current? Of course it could just be aged wiring and connections objecting to the damp weather...Nick Link to comment Share on other sites More sharing options...
Roger Posted January 17, 2008 Share Posted January 17, 2008 I know it sounds silly but check that there is enough oil in the box as low oil will make the overdrive jump out.Roger Link to comment Share on other sites More sharing options...
GT6DavidMK1 Posted January 17, 2008 Share Posted January 17, 2008 Hi Darren,Check the wiring in the Gear stick, my PI does the same, I have traced the fault to the gearstick if I hold the gearstick lower down overdrive worksDavid. Link to comment Share on other sites More sharing options...
Tim Bancroft Posted January 17, 2008 Share Posted January 17, 2008 Bet its where the wires come out of the base of the gear lever?What a design! Link to comment Share on other sites More sharing options...
moosetvr Posted February 4, 2008 Author Share Posted February 4, 2008 Update on progress - I have changed O/D switch and harness in gearstick, relay and internal harness going to relay and switch, and changed the gearbox oil. Problem is still the same. This, I believe, only leaves the wiring down to the inhibitor switch and the inhibitor switch as possible faults. Had a quick look and with big hands like mine it all seems very inaccesible. Anybody got any tips or hints on how you can easily get to the inhibitor switch on an A type overdrive ? Or any other ideas what may be at fault ?? Thanks, Darren. Link to comment Share on other sites More sharing options...
Glenn Posted February 4, 2008 Share Posted February 4, 2008 Most cars I've seen have very ropey Overdrive wiring. However I can confirm that the inhibitor does play up too.I recently had my 'box out and the inhibitor was intermittently faulty. On removal there was a lot of crud around the switch plunger. A clean up with WD40 and a toothbrush helped but not completely. There seemed to be some wear either on the switch or selector. I removed the 2 fibre washers to compensate and replaced (with a little silcone to seal it from water ingress). It works reliably now.Can it be done with the box in situ? You might manage by dropping the gearbox crossmember as far as it will go. Worth a try anyway. You'll need a really big open ender - I think it's 1 1/2 AF. The switch shouldn't be too tight. Good luck! Link to comment Share on other sites More sharing options...
moosetvr Posted February 6, 2008 Author Share Posted February 6, 2008 Might just take the plunge and replace the solenoid on Saturday as GTEVO suggested. Can that be done without dropping the box down ?? (sorry very wet here and dont want to get soaked looking at gearbox in work car park !!!) Link to comment Share on other sites More sharing options...
Jason Posted February 6, 2008 Share Posted February 6, 2008 Check the inhibitor switch mountings, mine is out of alignment, figured that out on the 10CR in a German carpark by torchlight after pulling the tunnel out! Whacked it with a hammer and all was well - well sort of, I have OD in 4 but not 3 - that still needs sorting! Access in the Vitesse is a lot easier :-) Link to comment Share on other sites More sharing options...
.thumb.jpeg.b15b81ef10abeea1c3039ae03c4a9f3a.jpeg)
Recommended Posts
Archived
This topic is now archived and is closed to further replies.