Overdrive sticking

[John Mellor]

Hi all, od playing up a bit. On a few occasions after a 10 + mile run the od fails to disengage but will free itself  after a variable time. Solenoid can be heard clicking with switching in or out.

Checked oil and took 150 mls top up, is this an explanation. Obviously time will tell next time I'm out for a run. Going to the Donington Historic meeting early May hopefully with a working od 

[Lebro]

Usual symptom of low oil level is that the O/D will not come in, not the other way round.

Bob

[james christie]

I find that the boot around the solenoïd can get a bit crumpled or accumulates a lot of road dirt.

Have a poke around from underneath to try and clean things up. Unfortunately if the boot is a bit mangled, nobody as far as I know, will sell it to you on its own although I have managed to buy it from Denis Welch with only the plunger. Others insist on including the whole solenoid.

james

 

[Motorsport Mickey]

Sometimes a build up of gunge on the cone clutch and easy driving.

Take it onto the open road and at 4000 revs in second gear WITHOUT removing foot off throttle operate the overdrive, it should engage by the time your finger leaves the operating arm. If it works great, continue to try this for maybe 5 or 6 operations. If it sluuuurrrrsss in it's removing contamination from the cone clutch, it can't harm it, Engage and disengage overdrive under power at all times, that's how they are designed.

It should get better as the contamination is removed.

Mick Richards

 

[dingle]

I have found that a whack with a mallet to the brake ring will free the cone clutch.

Berry

[BlueTR3A-5EKT]

Could it be dirt in the spindle valve.   The one under the cap with the ball and spring.  The spindle has holes in it which are quite small holes that direct oil under pressure and therefore will allow pressure decay when disengaged.

Items 19 onwards circled in image.

Edited April 16 by BlueTR3A-5EKT

[John Mellor]

Thanks all. Found a Laycock manual describing perfectly what happens with partially obstructed spindle valve. As oil pressure reduces od is released.

Change into od at 4k rpm wasn't that quick so will try a few more before going for the spindle valve.

Guess that means transmission cover has to come off. Sod it, knackered knees and shoulders make it difficult.  Guess my decision to sell this year is the right one.

John Mellor 

 

[John Mellor]

Hi all, tried 4.5K rpm in second much quicker change than yesterday then successful disengage. Three more times eureka - however on a gentle 4th change 🤔 stuck again.

Ah well it will be free within an hour or two so I'll try again today.

Dreading having to remove tunnel if it proves to be spindle valve blockage. Thought of it makes my back, neck and shoulders ache. 800 ibuprofen before and after helps - time to sell!!

[Rob Salisbury]

Take the steering wheel off to give better access, (though protect the end of the column from head clash), weight lifter style back support belt along with the ibuprofen, power tool for the cover fixing screws (cordless drill or similar), rubber mat for the knees, no need to sell the car!!

Cheers Rob

[John Mellor]

Hi all, tried 4.5K rpm in second much quicker change than yesterday then successful disengage. Three more times eureka - however on a gentle 4th change 🤔 stuck again.

Ah well it will be free within an hour or two so I'll try again today.

Dreading having to remove tunnel if it proves to be spindle valve blockage. Thought of it makes my back, neck and shoulders ache. 800 ibuprofen before and after helps - time to sell!!

[John Mellor]

Few more aggressive changes in and out at 4500 rpm led to successful changes.

Donington here we come, will try to park allowing forward direction "just in case"

Edited May 1 by John Mellor