Paul Harvey Posted July 7, 2010 Report Share Posted July 7, 2010 (edited) Got my overdrive working perfectly after advice on this forum yesterday but only for a short while. I fitted a new relay and we discovered the previous wiring was incorrect. After refitting everything ok - o/d only engaged in 2+3+4 gear and enaged/disengaged promptly on request. However, after a few miles of test there was suddenly a loud and worrying 'clonking' from the overdrive when engaged which disappeared completely when disengaged. I fear something terminal has occurred! However, before going any further I though I should ask you guys for your opinion. What is likely to be causing a very loud clunking from the overdrive unit and how is it fixed! Edited July 7, 2010 by Paul Harvey Quote Link to post Share on other sites
RogerH Posted July 8, 2010 Report Share Posted July 8, 2010 Hi Paul, have you any more info - Does it happen in 2, 3 and 4 Any particular speed Accelerating, decelerating or constant speed Do the revs change at the clonk oger Quote Link to post Share on other sites
Tr4Tony Posted July 8, 2010 Report Share Posted July 8, 2010 Hi You need to stop using it asap as there isnt much to clonk in an OD unit and what is there wont survive long. It sounds like one of the planet gears has become dislodged (the pins pull out and the gear tilts, which means its getting chewed up in there) and im afraid thats a gearbox and OD unit out job to deal with. Worth also checking thats its not an overdrive 'clonk', but a gearbox vs chassis noise. The gearbox mount may have failed (rubber and steel debond on the repro mounts), or the large damper on the rear of the gearbox is knocking against the chassis due to the mount failing, exhaust banging for similar reasons etc. etc. Best advice I can give is to talk to someone capable like Overdrive Repairs Services in Sheffield once youre sure its an overdrive problem - Peter Eggington and he will give you a fully informed view. Regards Tony Quote Link to post Share on other sites
Paul Harvey Posted July 8, 2010 Author Report Share Posted July 8, 2010 The clonking seemed to be related to road speed rather than revs as I quickly changed from 2nd to 3rd to 4th and then disengaged the overdrive. Having said that I was reluctant to check it out for fear of causing further damage. Once I got the car home I had a couple of very brief low speed tests in 2nd and the knocking was consistent and instant on engagement. Seemed like something revolving in the casing and banging against the inside. What surprised me most was that the car seems perfectly normal in all gears with overdrive disengaged. Unless someone out there can suggest a DIY fix I propose to take the car to a specialist - my question is whether it is safe to drive there (with overdrive deactivated) or whether I need to trailer the car. Advice please. Quote Link to post Share on other sites
Alec Pringle Posted July 8, 2010 Report Share Posted July 8, 2010 Hi Paul, if it's an internal overdrive fault, continuing to drive the car could prove to be an expensive error. Or more likely will prove to have been an expensive error ! Winch it onto a trailer. Cheers, Alec Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.