Overdrive occasionally fails to disengage

[Nigel Clark]

I've recently fitted a rebuilt gearbox and J-type overdrive which will hopefully survive the extra torque of the 2.5 litre engine in my GT6. Both overdrive and gearbox have been rebuilt.

Occasionally, the overdrive fails to disengage and will remain engaged even when changing down to first and second gears. It seems to disengage after the car has been stationary for a few seconds, whether the engine is idling or switched off. After pausing for it to disengage, it will engage and disengage normally in third and fourth gears, until it sticks again. This seems to happen once the engine and gearbox have warmed up, not when cold.

It's puzzling me... I'm wondering if the solenoid is sticking as that's the only component that wasn't replaced, the old solenoid was tested, found to work okay and put back. Any ideas please? Does a sticky solenoid seem plausible? Or some other cause?

Thanks in advance,

Nigel

PS: I'm aware of the danger of reversing with overdrive engaged and am trying hard to avoid that pitfall.

[Pete Lewis]

i would remove the solenoid  ( thin 1"af spanner job\)  and remove the small 10mm circlip in its end and pull the inner spool /piston out and examine the small 0 rings    the thing should be free and rattle if given a good shake if its sticking the OD will have a mind of its own

best not to use grips on the sol body as that if its tight can wreck the body 

James Paddock Limited - Triumph Stag, Spitfire, TR6, TR7, GT6, Vitesse, Herald Parts and Spares Specialists. OVERDRIVE SOLENOID J TYPE SPANNER(NKC41T)

had a look at overdrive repairs sheffield but they dont list the internal 0 rings   so a call might work 

everyone lists the two outer body 0 rings not the piston ones  ....they probably just want to sel you a £120 replacement 

there are reworked ones for £89 but all you need is two small rings

 

Pete

[Nigel Clark]

Thank you Pete.

I was thinking along the same lines but hadn't realised there are those small internal O rings to replace. Tunnel cover out again, what joy! I wonder if it's worth trying spraying silicone lubricant at the solenoid from under the car to see if that frees up the solenoid piston.

Nigel

[Pete Lewis]

well the piston is in a load of oil anyway

the sol may unscrew by hand , it seats with a sealed washer 

you will get a cupfull of oil out when you remove the sol .

when i did mine ( a day after buying her)  kit - operating piiston  nkc0099k  from chris witor 

Chris Witor Triumph Specialist

Pete