simonjrwinter Posted December 11, 2015 Report Share Posted December 11, 2015 Just had a "fully reconditioned" A type gearbox and overdrive fitted to the Stag (son in law's car) Gearbox works fine but overdrive will only engage on a constant throttle at about 2000 rpm and as soon as any throttle is applied, overdrive immediately drops out again. Now I'm sure the chap who rebuilt it will stand behind any issues, but I'm keen to know if anyone else has had an issue similar to this, and if so what caused it? Any advice appreciated. Simon Quote Link to post Share on other sites
Rob Salisbury Posted December 11, 2015 Report Share Posted December 11, 2015 Hi Simon, check the electrics are working properly first, then check and adjust the solenoid, if necessary hold the lever in position and see if it drops out of overdrive on power (two people needed for this to be safe), if this fails then something in the overdrive is wrong or out of adjustment. You will need to check the hydraulic pressure build up when running (it's around the 400psi mark), if it's a lot lower then something is wrong with the pump/accumulator piston/pump valve setup, maybe the spring set has been incorrectly installed (the short ones where the long ones should be etc), and finally from experience a broken or missing circlip 69 (in the Moss Cat,) gives this effect of engaging on constant or trailing throttle, but slipping out under power. Sorry but most of these fixes are a gearbox out job. Cheers Rob Quote Link to post Share on other sites
Stag powered Posted December 13, 2015 Report Share Posted December 13, 2015 I found out to my cost that it is easy to install the springs incorrectly, and got a similar problem to yours. In my case all the springs were the same length, but half of them have thicker coils which I didn't notice when installing. The thick ones will coil bind when fitted in the wrong position due to being mounted on a step, and this stops the overdrive engaging. Neil Quote Link to post Share on other sites
Motorsport Mickey Posted December 13, 2015 Report Share Posted December 13, 2015 "The thick ones will coil bind when fitted in the wrong position due to being mounted on a step, and this stops the overdrive engaging" Hi, so just to be clear can you confirm which thickness springs go where ? Mick Richards Quote Link to post Share on other sites
Nick Jones Posted December 13, 2015 Report Share Posted December 13, 2015 Check the wiring and inhibitor switches first. If it engages at all then it's more like to be an external electrical problem IMO. Nick Quote Link to post Share on other sites
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