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Anything and everything Vitesse.
Section : Gearbox
Clutch, gearbox, overdrive, propeller shaft.
Posted By : Jason Green, 03-Jan-2006, 04:18pm
OK, next problem.
After 25-30 minutes on the motorway my overdrive starts to drop out and come back in again. At slower speeds I notice that there is a short circuit type
sound when this happens. So I had a look and all the wiring looks in good order; the electrical arcing type sound seems to be from the solenoid area. I
wound a bit of insulating tape around the connections just to be on the safe side as I could imagine some moisture from the road gets thrown up there and
takes 25 minutes to seep that far.
Any ideas as to what to check and/or replace first?
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Posted By : Ian Osprey, 03-Jan-2006,
08:51pm
Hi Jason.
I'm not an overdrive expert, but here's my tuppence worth.
These relays are electically operated mechanical switches, so they do 'click' on and off.
It sounds to me that the relay is switching on and off at the wrong times. I'd suggest that either the relay is needing replacement or the overdrive
switch or it's wiring needs replaced.
Problem is, as with all intermittent faults, how to diagnose?
Personally, I'd jury rig a 'permanantly on' supply to the relay, and test that out. If it still cuts out, suspect the relay, if not, then the switch
and wiring.
I'm sure someone'll suggest something more definative
Ian
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Posted By : Andrew Stanton, 04-Jan-2006,
06:49am
Hi Jason,
My experience in matters concerning overdrive relays is that its the overdrive switch that's the problem. A special place in hell needs to be
reserved for the jerk who designed it. It works on the basis of a springloaded lever, which when the switch passes a certain point springs the
lever into contact, and does the same when it is turned off. The snag is that over time the contact surfaces become pitted and the connection
becomes unreliable.
As in all matters electrical diagnosis comes from a methodical approach. There are three possible causes to your problem; 1. The solenoid itself,
2. the wiring, 3. the switch.
Examine them separately.
1. Use a circuit tester to check out the integrity of the solenoid. All electrical items offer a certain resistance to a current. If your solenoid
doesn't then it is probably faulty and needs replacing. You'll find the specification in the workshop manual.
2. Examine the wires. Look for corrosion on the connectors at all points in that particular circuit; where they connect with the switch detecting
third and fourth gears (on the oil filler plug on the gear box), on the overdrive switch, and on the overdrive solenoid. Use a circuit tester to
check that they are carrying a current.
3. Use a circuit tester to check the switch. Alternatively rig up a temporary switch, bypassing the one in the gear lever, and see if that deals
with the problem. I suspect from what you have described the problem lies here.
All the best