Jim A Posted August 17, 2023 Share Posted August 17, 2023 Hi. Quick question. My Mk1 is finally on the road. I got an OD gearbox installed. We’re still shaking it down and we’ve found the OD slips out at times. It’s a bit like kickdown and happens mostly when you hit a hill and put some power on. Any thoughts? Thanks, Jim Quote Link to comment Share on other sites More sharing options...
Tim Bancroft Posted August 17, 2023 Share Posted August 17, 2023 Probably an idea to talk to an overdrive specialist. Have a look at this site, they have a trouble shooting page. http://www.odspares.com/ 1 Quote Link to comment Share on other sites More sharing options...
glang Posted August 17, 2023 Share Posted August 17, 2023 First check gearbox oil level👍 1 Quote Link to comment Share on other sites More sharing options...
Tim Bancroft Posted August 18, 2023 Share Posted August 18, 2023 That is a good idea, oil level moving around due to gravity. 1 Quote Link to comment Share on other sites More sharing options...
glang Posted August 18, 2023 Share Posted August 18, 2023 I think its probably the cone clutch worn and slipping (hope no additive has been used in the oil) but best to check easy stuff first👍 1 Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted August 18, 2023 Share Posted August 18, 2023 Slipping, or dropping out (going back to direct drive)? Different problems with different causes. The latter could be low oil or a dodgy electrical connection somewhere. The former is likely internal- worn clutches or possibly low operating pressure. 1 Quote Link to comment Share on other sites More sharing options...
glang Posted August 19, 2023 Share Posted August 19, 2023 Yes could be either but 'happening on hills' sounds more like slipping to me☹️ 1 Quote Link to comment Share on other sites More sharing options...
Martins Stag Posted August 21, 2023 Share Posted August 21, 2023 (edited) If the gearbox oil is unknown and you don't know if any additive has been added by the previous owner, i think I may be tempted to drain all the oil and clean all the filters, refill and see if it makes any difference? If not, as it has been mentioned, it sounds like the cone clutch is slipping and needs replacing/relining.... Edited August 21, 2023 by Martins Stag 1 Quote Link to comment Share on other sites More sharing options...
JohnD Posted August 21, 2023 Share Posted August 21, 2023 On 17/08/2023 at 19:26, Jim A said: Hi. Quick question. My Mk1 is finally on the road. I got an OD gearbox installed. We’re still shaking it down and we’ve found the OD slips out at times. It’s a bit like kickdown and happens mostly when you hit a hill and put some power on. Any thoughts? Thanks, Jim My underline. That is NOT a slipping clutch cone on the O/d! As Nick says, probably an electrical connection. John 1 Quote Link to comment Share on other sites More sharing options...
Jim A Posted August 26, 2023 Author Share Posted August 26, 2023 Thanks for the replies all. It will be a winter job to get it sorted. Too busy trying to get some miles on it for now! 🚗👍 Quote Link to comment Share on other sites More sharing options...
glang Posted August 26, 2023 Share Posted August 26, 2023 Great, while driving it try to get a feel for whether your losing drive (OD slipping) or its just momentarily dropping out into non OD. Unfortunately the symptoms will be very similar but perhaps the first actually causes a drop in speed while the second not? Also the second shouldnt be related to engine load so youll see the revs go up momentarily while just cruising on the flat.... Quote Link to comment Share on other sites More sharing options...
Rutty Posted August 27, 2023 Share Posted August 27, 2023 Have you checked the solenoid adjustment. If its not pulling the actuating leaver all the way you could have low oil pressure not fully holding the OD in. It's quite easy to do on a D type I have no experience of other types of OD but I would expect it to be similar. Quote Link to comment Share on other sites More sharing options...
glang Posted August 27, 2023 Share Posted August 27, 2023 Like it Rutty and if slipping it needs to be sorted sooner rather than later as it wont do the friction material any good.... Quote Link to comment Share on other sites More sharing options...
PaulGT6 Posted Friday at 08:20 Share Posted Friday at 08:20 I have a similiar problem. When driving at 60mph (3000 rpm) and engage the OD, initially nothing happens. If i take my foot off the accelerator slightly, the revs drop to 2000 rpm as if the OD has engaged. However, as soon as i touch the accelerator the revs jump back to 3000 rpm as if i have switched the OD off. I have a 73 mk3 GT6. I assume the gearbox oil / fluid is shared between the gearbox and the OD unit. The gearbox oil is full. I have read somewhere the OD has its own transmission fluid....... I can hear the solenoid click when engaged (stationary with engine running) in 3rd and 4th gear, no click in 1st or 2nd which is good. Thanks in advance for any tips Quote Link to comment Share on other sites More sharing options...
Clive Posted Friday at 09:30 Share Posted Friday at 09:30 1 hour ago, PaulGT6 said: I have a similiar problem. When driving at 60mph (3000 rpm) and engage the OD, initially nothing happens. If i take my foot off the accelerator slightly, the revs drop to 2000 rpm as if the OD has engaged. However, as soon as i touch the accelerator the revs jump back to 3000 rpm as if i have switched the OD off. I have a 73 mk3 GT6. I assume the gearbox oil / fluid is shared between the gearbox and the OD unit. The gearbox oil is full. I have read somewhere the OD has its own transmission fluid....... I can hear the solenoid click when engaged (stationary with engine running) in 3rd and 4th gear, no click in 1st or 2nd which is good. Thanks in advance for any tips Oil is shared between OD and box. So that is the easiest possibility crossed off. Have a read through this https://canleyclassics.com/?archive=the-d-type-overdrive Quote Link to comment Share on other sites More sharing options...
glang Posted Friday at 10:15 Share Posted Friday at 10:15 To me it sounds like the friction surfaces are slipping so that OD doesnt grip until the power is taken off and then slips as soon as it returns. This can be worn friction material or low hydraulic pressure. The oil filter, which if blocked might explain the latter, is accessible from the underside of the OD... Quote Link to comment Share on other sites More sharing options...
glang Posted Saturday at 17:14 Share Posted Saturday at 17:14 Meant to include the possibility of there being an anti friction additive in the oil which is a no no... Quote Link to comment Share on other sites More sharing options...
.thumb.jpeg.b15b81ef10abeea1c3039ae03c4a9f3a.jpeg)
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.