tr-pete Posted September 1, 2016 Report Share Posted September 1, 2016 Hi , if anyone has any advice, i have owned my tr4a for 10 years and the overdrive has always worked perfectly in 2nd and 4th byt not third. Currently doing jobs on the car and stripped the gear box tunnel out expecting to find three switches on top of the gearbox one with either a loose wire or switch needing screwing down etc. But there is only two switches. Does that mean i only have overdrive in second and fourth or can anyone help? It is a j type box btw..thanks pete Quote Link to post Share on other sites
Steves_TR6 Posted September 1, 2016 Report Share Posted September 1, 2016 J type box should have overdrive on third and fourth, not second. So perhaps the switches are fitted/wired incorrectly? An expert will be along shortly ...... Quote Link to post Share on other sites
MRG1965 Posted September 1, 2016 Report Share Posted September 1, 2016 Hi Pete, there should be two switches. One does 2nd and the other covers 3rd and 4th. There are small grooves in the selector rods that as the gear is selected a plunger drops in the groove and the switch operates and earths thd circuit to operate the solonoid. I'd suspect the groove for 3rd is either not there or full of crud stopping the plunger droping in to the groove. Take out 3/4 switch, just unscrews and check the groove. Cant be anythong else really as thd systems works, has to be the 3rd poxition groove issue. Mark Quote Link to post Share on other sites
Drewmotty Posted September 1, 2016 Report Share Posted September 1, 2016 I think Mark is about right. The switch position can't be far out or it wouldn't work on 4th but it may not be dropping quite enough at the 3rd gear detent and may need shims under the switch adjusting to put things right. Quote Link to post Share on other sites
boxofbits Posted September 1, 2016 Report Share Posted September 1, 2016 +1 on Mark's comment. Unlikely to be the overdrive per se, and most likely to be a selector or selector switch issue. Had a similar problem on my 'A' type 3rd gear recently which was a selector switch problem. Kevin Quote Link to post Share on other sites
tr-pete Posted September 1, 2016 Author Report Share Posted September 1, 2016 Many thanks this is fab information, i do seem to recall that maybe the overdrive did work in third when i first had the car, all be it i think it used to jump in and out every second so i stoped trying to use it in third but now I'm testing my memory. So a dirty groove would make sense. I guess a multimeter would trace the offending switch by moving the gear stick and prove when fixed. Many thanks all and any other help greatly appreciated...pete Quote Link to post Share on other sites
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