Overdrive snag?

[100+]

There's a rapid clicking coming from the overdrive relay when I engage overdrive (D-type on a GT6 III engine and box).  As well as this, the overdrive seems reluctant to disengage sometimes...

Wiring is good, when stationary, the relay and solenoid click just fine (ie once) in and out of overdrive and the 3rd/4th only isolator switch works as advertised, but driving along, things aren't good.   :-/

It's an intermittent snag, sometimes the overdrive goes in and out ok.

Dirty oil?  Filters need a clean? Thinking laterally, the battery had a hard time over winter (still shows 13v across the terminals with engine turned off, so isn't completely shot).  It's probably not the battery though.

Thoughts please guys!

[Pete Lewis]

sounds like a common problem of the wires up the hollow gear stick have chaffed through internally
Pete

[100+]

Oh sorry chap, the car's a Vitesse with a column stalk.  I will check for chafing, but when I renewed the wiring I was careful to secure everything properly and use grommets where necessary.  However, brittle old insulation can crack, I grant you.

It does feel like something internal to the unit though.

I'm beginning to suspect the solenoid might not be at its best.  Oh joy, just love changing the overdrive solenoid, groooan! :o

[nang]

Suggest check relay wiring, loose / dirty connection, faulty earth?

[piman]

Hello 100+,

if the relay is chattering then it won't be inside the overdrive. As mentioned earlier check all connections.

Alec

[Freebird]

And check the adjusment of the throw of the arm that the solenoid operates. There is a hole in the arm that should line up with a hole in the casting when it's correctly adjusted.

[heraldcoupe]

Assuming you have a D-type overdrive, the solenoid fitted to that type incorporates two windings.

There is a primary winding which draws higher current, this is what initially moves the armature.
Once the overdrive has switched and the primary winding has moved the armature, the primary winding is switched out and a secondary holding winding (lower current) takes over to hold the armature in it's 'ON' position.

Constant clicking is an indicator that the secondary winding is not coming into operation, either because the winding itself has failed, or because the switch within the solenoid is not operating correctly.

Cheers,
Bill.

[100+]

Ah, that makes sense Bill, thanks.  I thank all for mentioning the connections to the relay, but they are all excellent (if I do say so myself)...I always solder my joints and work to quite a high standard in wiring, so am pretty content it's not just a duff connection.  

The fact that the overdrive sometimes stays engaged even when the relay has clicked 'off' when the stalk is flicked up, meant that I was suspicious of the solenoid.  

I will double check the obvious stuff first though, because getting it off is such a monumental pain in the backside.(angry)

Are NOS solenoids available from you Bill?  I am not keen on nasty reproduction rubbish, I'd even prefer good secondhand....

[heraldcoupe]

100+ wrote:

Are NOS solenoids available from you Bill?  I am not keen on nasty reproduction rubbish, I'd even prefer good secondhand....

Afraid I can't help with that. It's one of those items I bring in to order, so nothing useful on the shelf.
In all honesty I'm not aware of any problems with new solenoids, though as you've gathered, it's not something I handle too regularly,

Cheers,
Bill.

[Pete Lewis]

if you take the plate off the side there is ahole in the lever pulled by the sol. if set correctly it aligns with a similar hole in the main case, a 3/16" drill will act as a dowel to check alignment,  has the have the solenoid energised,
if its set short then the sol. plunger will not contact the cut out switch fitted in the sealed end of the sol.

as for supplies  
use  ODspares Rugby
       overdrive repairs sheffield    

Pete

[100+]

Thanks guys!

Quick update - I did the easy stuff first, and cleaned the electrical connections in the stalk switch with IPA.  Put it back and went for a spin.  About 2 seconds of chattering on the first engagement, then, once engaged, I lifted off the throttle and tried to disengage o/d.  It was funny, the car displayed no engine braking characteristics, and seemed to coast, with the o/d still in.  Anyway, continued use seemed to make it behave a little better.  The car is stored over winter, so it could be spring gremlins being exorcised.  I am going to continue to give it exercise in the hope that it fixes itself.  It seemed fine after 10 mins yesterday - let's hope that continues!