Overdrive question

[Dylan]

Hi All
Quick question - discovered a problem with the (J-type) overdrive at the weekend. It kept cutting in and out, but only at higher speeds, like65+. It was OK at 50-ish, so I thought unlikely to be simple electrical.

What do you reckon?
many thanks
Dylan

[jagorstag]

Only guessing, but could it do with an oil change?

[Marco Polo]

I would check the gearbox oil level first and also check the condition of the earth lead from the solenoid body to the o/d unit itself they get quite brittle, its easy to make one yourself. If you still have problems check the switch in the gear lever and then the wiring loom that runs through in the gear lever. Also check the continuity across the fuse box. If I remember correctly the o/d has its own separate fuse.
Let us know what you find.
regards,
Raoul

[Dylan]

Thanks both
Will follow up but it won't be for a couple of weeks. Overdrive was professionally overhauled last year but things could have happened since I guess. I suspected it to be not electrical as it switches in and out fine at lower speeds.
all the best
Dylan