[Healeys] Overdrive problem

[Michael Salter]

Hi Neil,
Based upon my experience i would think that the oil type is not likely to
be the real problem.
You should check that the operating valve is opening all the way as per the
workshop manual as that is very easy and can cause problems but again not
the most likely cause.
My bet would be that the pressure accumulator bore and piston are badly
scored and allowing oil to pass. This can, with considerable effort be
corrected without removing the gearbox.
Wear and damage on other parts can contribute to the leakage but most of
those, like the operating pistons require removal of the unit for repair.

-- 
Michael Salter

                         *I have BJ8 water pump kits!!*


On Sat, Oct 13, 2012 at 1:20 PM, Neil Blackshire
<neilblackshire at gmail.com>wrote:

> Hi Listers,
>
> I just got back from 2000 mile round trip in my 1960 3000, after about 1000
> miles sometimes the overdrive would not stay engaged up hill, as journey
> continued it gradually got worse until it would disengage straight away. I
> was reading about possible causes and solutions and in the workshop manual
> it says not to use extreme pressure oil,  I have been adding 75w80 extreme
> pressure oil to the gearbox since I have owned the car, 3 years (several
> litres) and before leaving on the journey I used 80w90 by mistake. I know
> that there are different views on which oil to use, but I thought to try
> draining oil and replacing with 20w50 engine oil but manual says removing
> filter drain plug  leaves about < pint in the overdrive. Could this small
> amount of oil still be a problem? Or am I just wasting my time anyway as
> the
> problem is more likely to be the clutches or an oil pressure problem.
>
> Any comments please.
> _______________________________________________