Ashley Posted July 19, 2012 Report Share Posted July 19, 2012 I recently fitted a new clutch to my car. Before reassembling the interior I tested the overdrive by listening for the solenoid switch cutting in and out. Felt very pleased with my self after a short test run during which clutch, gearbox and overdrive performed faultlessly. I was later brought back to earth when I discovered that once the car was up to temperature the overdrive would not work on 3rd. ( 2nd and 4th continued to operate normally). Suspecting a problem with the inhibitor switch, I bit the bullet and stripped out the car to get at the inhibitor switches. I cleaned and checked all the connections on the 3rd/4th switch and noted that it was only finger tight so turned it a 1/4 turn to tighten. Took the Good Lady and my Wife out for a long run during which overdrive behaved impeccably. Unfortunately the problem has returned, with the overdrive mis-behaving in 3rd gear only, once the car has warmed up. Have been through the search facility on the forum, and see that I am not the first suffer such a fate. However while I try to muster the strength to dismantle the car for a third time this summer, can anyone give any advise on the correct setting/ tightness for the inhibitor switches, or should I replace the switch? Quote Link to post Share on other sites
stuart Posted July 19, 2012 Report Share Posted July 19, 2012 It could be the switch adjustment or it could be wear on the ball end of the plunger on the switch where it contacts the detent in the selector shaft. The repro switches arent that clever so take your old one out and on the top of it you will see that the outer cover is peened over to hold the plastic centre section in place. Carefully bend back the tags and remove the top and you will probably see that the spring and plunger are rusty and the contacts have burn marks on them. Clean it all up and apply a little Vaseline around the plunger and then re assemble. When re-fitting there should be a thin shim washer underneath to provide adjustment. With a meter across the terminals try selecting third and see if you get continuity through the switch and that it shuts off when the gear is deselected. It may need shimming up or down to ensure operation, the switch should be a tight fit but dont overdo it as its aluminium threads. Stuart. Quote Link to post Share on other sites
Guest ntc Posted July 19, 2012 Report Share Posted July 19, 2012 Swap the switch for the reverse one works every time Quote Link to post Share on other sites
Rien Posted July 19, 2012 Report Share Posted July 19, 2012 Hi guys, if the switch are the problem, he would also cause problems in four sometimes. I clean the switches like Stuart do but I prefer to do the adjustments with a battery and a 21W lamp Maybe a loose selector fork, or is the gear lever against something? This does not explain why only when hot I think. Regards, Rien Quote Link to post Share on other sites
Ashley Posted July 19, 2012 Author Report Share Posted July 19, 2012 Thanks for the replies gents. Rien, what do you mean by is the gear lever against something? I have noticed that since reinstalling the gearbox, it will occasionally no longer have 1st gear selected after pausing at a junction. Is it possible that the lever is not travelling it's full forward distance? Ashley Quote Link to post Share on other sites
RogerH Posted July 19, 2012 Report Share Posted July 19, 2012 Hi Ashley, the rubber gaiter at the base of the gear lever can be too stiff. This will help in pushing both 1st and 3rd out of gear. If in O/D then 3rd gear can pop out of O/D but maintain 3rd gear drive. If it happens again hold the lever forward to prove one way or the other. Roger Quote Link to post Share on other sites
Ashley Posted July 19, 2012 Author Report Share Posted July 19, 2012 Thanks Roger, I much prefer a simple fix. I am away from home at the moment, but will test it out next week. Ashley Quote Link to post Share on other sites
Ashley Posted July 25, 2012 Author Report Share Posted July 25, 2012 Got home and put Roger's idea to test. The car will hold overdrive in 3rd if forward pressure is maintained on the gear lever. I have repositioned the gaiter at the base of the lever so that it shouldn't interfer ( took it out of it's correct seating and positioned it forward but lose on top of the transmission cover). The car hasn't jumped out of 1st gear since doing this, but sadly it will still jump out of overdrive in 3rd unless the gear lever has a small amount of forward pressure applied to it. I am thinking that my next move should be to remove the inhibitor switch, point a touch down there, and see what's happening when 3rd is selected. Has anyone got any suggestions? Ashley Quote Link to post Share on other sites
Rien Posted July 25, 2012 Report Share Posted July 25, 2012 Got home and put Roger's idea to test. The car will hold overdrive in 3rd if forward pressure is maintained on the gear lever. I have repositioned the gaiter at the base of the lever so that it shouldn't interfer ( took it out of it's correct seating and positioned it forward but lose on top of the transmission cover). The car hasn't jumped out of 1st gear since doing this, but sadly it will still jump out of overdrive in 3rd unless the gear lever has a small amount of forward pressure applied to it. I am thinking that my next move should be to remove the inhibitor switch, point a touch down there, and see what's happening when 3rd is selected. Has anyone got any suggestions? Ashley Yes see previous, clean switch and set it to the correct depth, try not more than one shim. Cheers, Rien Quote Link to post Share on other sites
Ashley Posted August 5, 2012 Author Report Share Posted August 5, 2012 Thanks for all your help so far Gents. I am now following Stuart's advice to clean up the inhibitor switch and re-adjust it. I have the guilty switch in my hand, but as yet have been unable to bend open the three tags that hold it together. I have be using a number of different screwdrivers that I have tried to prise under the tags, but fear that it is soon going to result in the total destruction of the switch. Has anyone got any suggestion on how I can carefully open these tags? Ashley Quote Link to post Share on other sites
Rien Posted August 5, 2012 Report Share Posted August 5, 2012 Thanks for all your help so far Gents. I am now following Stuart's advice to clean up the inhibitor switch and re-adjust it. I have the guilty switch in my hand, but as yet have been unable to bend open the three tags that hold it together. I have be using a number of different screwdrivers that I have tried to prise under the tags, but fear that it is soon going to result in the total destruction of the switch. Has anyone got any suggestion on how I can carefully open these tags? Ashley You can bent the tags outwards with a plier. Rien Quote Link to post Share on other sites
Ashley Posted August 5, 2012 Author Report Share Posted August 5, 2012 A number of different pliers have only eaten away some of the casing and given me blood blisters. Thanks for your help Rien, but I am going to have to admit defeat on this one. Quote Link to post Share on other sites
Rien Posted August 5, 2012 Report Share Posted August 5, 2012 A number of different pliers have only eaten away some of the casing and given me blood blisters. Thanks for your help Rien, but I am going to have to admit defeat on this one. Hi Ahsley, don't give up Good luck Rien Quote Link to post Share on other sites
stuart Posted August 5, 2012 Report Share Posted August 5, 2012 A pair of parrots (Water pump pliers) as illustrated by Rien will work but be careful of the casing as it is only ally. Stuart. Quote Link to post Share on other sites
Ashley Posted August 6, 2012 Author Report Share Posted August 6, 2012 Was a little worried that Stuart was referring to Rien and myself by starting with " a pair of parrots". I have now purchased a set of water pump piers and will try following Rien's excellent illustration. Thanks gents. Ashley Quote Link to post Share on other sites
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