Section : Overdrive

Overdrive problem

Posted By : David Langdon, 14-May-2003, 12:57pm

Hi,

I have a late model MkIII with a dodgy overdrive. I had a problem with the o/d switching in and out and eventually failing to engage at all. The problem (I thought) was down to some broken wiring. The wires, gear lever switch & solenoid have been renewed but the o/d now switches in & out very rapidly especially when accelerating. The problem does seem to improve as the car warms up but I haven't driven it for any great distance so its difficult to be sure. Any suggestions??

David

Followups :

Overdrive problem

Posted By : Dom Weaver, 14-May-2003, 09:22pm

Well, mine is doing exactly the same - except that it seems to get worse the further you go rather than improve...turned out to be electrical, suspected short circuit. I would be surprised if it was mechanical...
- Overdrive problem
  
  Posted By : Graham Reeks, 15-May-2003, 09:49am
  
  Have a look at this ... has proved fairly useful to me in the past:
  
  http://www.canleyclassics.com/infodatabase.asp?top...
  - Overdrive problem
    
    Posted By : Colin Lindsay, 23-May-2003, 03:29pm
    
    Off the top of my head and assuming that your gearbox is full of clean oil, then I'd agree this is electrical. If you can hear it over the noise of the engine - is there a clicking of the solenoid every time it cuts in or out? If you've replaced the wiring etc. then suspect your inhibitor switch; I've seen GT6 where the extension on the gear lever no longer makes adequate contact due to wear either in the switch or the activating lever. You can replace the switch if you haven't already but you can also bend the mounting plate slightly to allow better contact. Sometimes the heat from the engine causes expansion so the problem only starts once everything warms up.
- Overdrive problem
  
  Posted By : Rob Wegman, 11-Jun-2003, 11:29pm
  
  Don't forget the oil viscosity might influence the speed of operation. Dopes, generally reducing gearboz wear, can cause reduction of friction in the overdrive and are not advised.
  Since overdrive and gearbox share the same oil, this might be a source of the problem.
  Did you ever put dopes in, are you using the correct grade of gearbox oil?
  
  gr,
  Rob