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Overdrive clutch type

Posted: Sat Jun 15, 2019 8:41 am
by Rev Light
I understand, rightly or wrongly, that when an overdrive is engaged by the solenoid, that it is done via some sort of clutch arrangement. What type of clutch is this? Is it a disc with some sort of friction material, or some sort of centrefugal arrangement?

The reason, I ask, is that my overdrive is no longer engaging properly. It does a couple of times when cold, but drops out when it warms, never to return. I tried to top up the oil, but it wasn't that low and I barely put half a litre in. I am about to drop all the oil and replace it. I suspect that an additive might have caused an issue, although it's taken a couple of years to do it.

Regards

Steve

Overdrive clutch tyoe

Posted: Sat Jun 15, 2019 8:52 am
by scimjim
It’s a cone - with friction material. Sounds like it could be low oil pressure? I’d do an oil change first.

Overdrive clutch tyoe

Posted: Sat Jun 15, 2019 9:03 am
by halfpenny
Have you checked the gearbox oil level?

Overdrive clutch tyoe

Posted: Sat Jun 15, 2019 9:30 am
by Rev Light
Topped it up yesterday. The oil that overflowed has a definite grey colour to it. It's the only reason I mentioned additive, as I do not remember adding any. I did to my back axle, but for a different reason - not that it did any good. The books categorically says not to add anything to the oil in any overdrive gearbox.

Anyway, fresh oil sourced, car warm and up on ramps, time to drop the oil.

Cheers

Steve.

Overdrive clutch tyoe

Posted: Sat Jun 15, 2019 9:42 am
by TrevorG
If you have no luck, or if you want to do this prior to oil change....you can take the plate off the bottom of the overdrive unit and check the magnetic strip, the base filter, and if feeling strong, the pump filter. It's amazing how much crud gets there and affects the pressure.

Overdrive clutch tyoe

Posted: Sat Jun 15, 2019 11:02 am
by halfpenny
Also pull out the pressure relief valve and clean it up; these can get very mucky and sticky.

Overdrive clutch tyoe

Posted: Sat Jun 15, 2019 11:19 am
by scimjim
Pretty sure the magnetic strip and pressure relief valve were cleaned when the box was replaced 18 months ago wasn’t it?

Overdrive clutch tyoe

Posted: Sat Jun 15, 2019 11:22 am
by Rev Light
If the chunks of metal that fell out of my overdrive sump are anything to go by, then I thinks it's toast.....

Ho hum....

Overdrive clutch tyoe

Posted: Sat Jun 15, 2019 11:45 am
by scimjim
Oops - yep, that’s toast!

Overdrive clutch type

Posted: Thu Jun 20, 2019 5:24 am
by Rev Light
Last question, I suppose. ..
Am I at risk of losing drive all together?
I had planned to take it to France at end of next month. I am planning to go to the Somme via L'Havre, avoiding the major routes.
Cheers

Overdrive clutch type

Posted: Thu Jun 20, 2019 6:19 am
by willholderogri
That looks like a piece of thick wire .

Overdrive clutch type

Posted: Thu Jun 20, 2019 6:20 am
by willholderogri
Some sort of pin maybe that has been mangled

Overdrive clutch type

Posted: Thu Jun 20, 2019 6:22 am
by willholderogri
Closer look seems to be the remains of a thrust washer

Overdrive clutch type

Posted: Thu Jun 20, 2019 8:50 am
by Rev Light
Anyway, I drove it work this morning. 36 miles across the downs from Swindon to Bradford On Avon.

Overdrive clutch type

Posted: Thu Jun 20, 2019 9:02 am
by halfpenny
Send the photo to Dave Twigger at Overdrive Services in Rugby. He'll likely identify it for you, and the consequences.