Richardtr3a Posted May 5, 2005 Report Share Posted May 5, 2005 I have aproblem with the selection of overdrive when the car has run for about ten miles. It has been overhauled by a specialist and since then the solenoid will only operate the shaft when cold. The specialist claims that a small crack in the mounting plate allowed the lever to bind up on the solenoid shaft. The plate was replaced and there is no improvement. The new claim is that the spacer under the operating lever was missing and that allowed the lever to bind on the solenoid shaft. But the lever to shaft connection is one of the most agricultural parts of the entire car and is not a carefully engineered fit. I am having difficulty in understanding how a change in operating temperature would affect the lever in any way at all. Has anyone suffered this problem. I am currently £1,100.00 down and no overdrive. Please help. Quote Link to post Share on other sites
Don Elliott Posted May 6, 2005 Report Share Posted May 6, 2005 The operating shaft goes right through the overdrive, from the solenoid side to the other. There are O-Rings, one at each side to seal the shaft. If one or both of there O-Rings are tight, the shaft will bind and it will not get rotated up by the pull of the solenoid. Bill Piggott described this problem he had in California Another suggestion is that the solenoid may be getting hot and if the pulling coil in the solenoid isn't working - perhaps by a loose wire at a solder joint that opens when it gets hot, then it's not pulling the actuating lever up. Try removing the solenoid and drive the car with the tunnel off. Connect a coat hanger or similar wire to the lever and which you can pull up while you are driving. If you pull up on the wire and the lever rotates upwards and turns the shaft, then the O-Rings are not the problem. If the overdrive engages when you pull up on the wire, then the overdrive is fine and the problem is in the solenoid. Don Elliott, Original Owner, 1958 TR3A, Montreal, Canada TR Register member since 1987 Quote Link to post Share on other sites
unclepete Posted May 6, 2005 Report Share Posted May 6, 2005 What about the gearbox overdrive switches? They need to be shimmed and set up quite carefully to avoid dropping the solenoid out under vibration or heat expansion. If the overdrive and gearbox have been in and out of the car the switches may have to be set up again - not a difficult job. Run the car up until you get the problem with the overdrive. Turn the engine off. Turn the ingnition back on again (don't start the car, this will enable the overdrive circuit, without the engine running) then try putting her in and out of gear with the overdrive switch on. You should hear the soleniod clicking in and out. If it dosn't at least you know its electrical. Overdrive relay Overdrive switch (on dash) Overdrive switches (on remote gearbox top selector) Sometimes you have to look at the simple bits before diving in and stripping the whole car apart. good luck Pete Quote Link to post Share on other sites
Guest chris jameson Posted May 8, 2005 Report Share Posted May 8, 2005 Richard, I had a problem with my overdrive dropping out/not engaging when the car had warmed up. I didn't have the solenoid adjusted correctly, in that it didn't rotate the operating lever enough to engage. For some reason, the overdrive engaged quite happily when cold. After adjusting the solenoid, I noticed a much more `aggressive' engagement (which I now believe to be correct), and it stays engaged.... Cheers, Chris Quote Link to post Share on other sites
Don Elliott Posted May 8, 2005 Report Share Posted May 8, 2005 I have always switched into overdrive with my right foot hard on the pedal. Under acceleration, the overdrive should just engage smoothly - much like an automatic gearbox. If you let up on the pedal and switch into overdrive, there will be a loud "clunk" from the gearbox/overdrive which I can only assume is bad for the mechanicals inside. Is this what you refer to as "aggressive" ? The TR3A overdrive should have a pressure of about 325 psi. The later TR6 overdrive reportedly has a higher pressure and many TR6 owners de-clutch while they are switching into overdrive. I feel that the TR2 to TR3A which was designed as a competition car would lose time if drivers de-clutched while shifting into overdrive. Don Elliott, Original Owner, 1958 TR3A, Montreal, Canada Quote Link to post Share on other sites
Mychael Posted May 8, 2005 Report Share Posted May 8, 2005 You can also get a smooth change by "feathering" the throttle as you switch in the o/d. It's fun to practice the co-ordination but as you say, you can also get a good change keeping the power on. I find it harder to get a smooth o/d change and lower revs and smaller throttle openings and will sometimes "flick' the clutch as I engage. Mychael Quote Link to post Share on other sites
Guest chris jameson Posted May 9, 2005 Report Share Posted May 9, 2005 Don, I would call it more of a `thump' than a `clunk'...Just a matter of keeping the power on...From talking to local owners, I think it is correct.. Cheers.. Quote Link to post Share on other sites
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