Overdrive relief valve

[Paul Domoney]

I have still to resolve the slipping overdrive problem but having replaced the overdrive unit and gearbox for the third time I think I have narrowed down the problem to the relief valve. If this is the case then at least I don't have to remove the gearbox yet again!! I am suspicious of the spring in the relief valve as when I first took it out the spring had been packed with washers. This tells me that it may not be the original spring. The oil pump works at a hell of a pressure so I guess the quality of the spring is critical. Can anyone give me the spec of the spring and are they available?: The book also talks about a modified plunger relief valve available as a kit. Are these available? Any advise would be much appreciated.

 

[Mikeflbmer]

Relief spring

I have a Laycock Overdrive service manual...I will find it and look to see if spring spec is there...mike

 

[Paul Domoney]

Thanks Mike. Look forward to hearing from you. I have looked at all the previous threads on this subject but have not come accross any discussion on the relief valve.

 

[Paul Domoney]

It has taken a long time and the gear box and overdrive have been out three times but I think I have solved the problem of the slipping overdrive. As I suspected it was the relief valve or rather the spring in the relief valve. I always suspected that the spring was too short even though it was the correct length as per the book. Because I did not have another spring I put in three washers to either effectively lengthen the spring or alternatively add to the pressure. Two test drives later I have no slip at all and the overdrive works perfectly. Working on the basis that "If it works don't fix it" I am not going to put in a longer spring but leave the three washers in place.