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Agrace

Hot Overdrive

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Quick question:

With J-Type overdrive, works like a charm when cold, but fails to engage when hot.

Solenoid works fine. O-rings replaced. Oil level good.

As soon as the car is hot, no engagement.

 

Any ideas?

 

Thanks

Andrew

 

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O/d works on oil pressure, generated by an eccentric on the input shaft, whose valve is opened by the solenoid.      So if it doesn't work when hot, either indicates that gearbox oil (shared with the O/d) needs replacing, the eccentric is worn or the valves are not sealing. 

Checks possible by testing the oil pressure at the connections beneath the O/d body, but they are very high - hundreds of PSI - and best done by a specialist.

John

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is it the right oil ?

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8 hours ago, Agrace said:

Can you let me know the correct specification of oil required?

I use gear 40 as recommended by gearbox rebuilder. 

3082F7F9-1BF0-434F-8AB3-7D8FACBEDAC6.jpeg

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I agree with Andy above, hot solenoids get sticky. 

No cost test.

Raise car, take a 12 volt line from battery, (fused if your a purist) Ignition off get under car connect to solenoid, clunk, disconnect and reconnect, clunk, repeat 40 times as it heats the solenoid has a smaller "clunk" with each energisation.

Helped me diagnose my J type solenoid problem. - By the way if you need to replace a solenoid Buy a purpose made J type spanner from one of the suppliers, or cut one down and thin the jaws of an old spanner. Swapping is a genuine five minute job with a correct spanner but a real PITA trying and failing when using your regular spanners.

Alan

 

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