[Healeys] Transmission / Overdrive or Clutch slippage

sentenac.rw at gmail.com sentenac.rw at gmail.com
Thu May 20 17:03:02 MDT 2021

Hola Rafael,

The possible good news is that if the overdrive worked before
restoration, whatever is wrong might be simple and easy to fix.

Here is a start:  With ignition on and overdrive dash switch on and
gearbox in neutral:  if you move the shift lever  to the right so you
can shift into third or fourth gear, can you hear a click from the
overdrive solenoid?  You should hear it.  Move to left and  it should
shut off.  Repeat this a couple of times to be sure.

No click suggests that at least one of the problems is that the
solenoid is not operating. This would keep the overdrive from
operating.  Time to replace the solenoid.   If you can hear the
clicking, then the shifting lever on the overdrive may not be adjusted
properly.  The shop manual is helpful here and there are some tricks
to try if they are needed.

It is possible to manually move the solenoid shifting lever while the
car's wheels are off the ground securely and safely, and the drive
train from engine to wheels is carefully brought up to speed in 3rd or
4th gear.  This should shift the overdrive in and out.  This is
dangerous and should be done by someone with experience and
understanding.  Rotating parts can catch clothing with disasterous

There are many more diagnostics but I am not competent too describe or
to direct you in them.


On Thu, 20 May 2021 21:41:56 +0000 (UTC), you wrote:

>Hi all,
>Last year I requestedyour help regarding a strange overdrive or slippage problem I have in my 1962Tricarb BT7. 
>I received veryvaluable comments and suggestions but sadly the problem persists: Overdrivewould not activate under any circumstances and when the engine / transmissionis warm and we engage reverse, the engine revs but the car won´t move. 
>There is slippagesomewhere in the transmission / clutch or overdrive. When the car is cold,reverse engages without any issues. This only happens in reverse gear after thecar has been driven a few miles and the engine and transmission are warm.Forward gears engage all the time without any issues.
>The car has beenrecently restored. Before the restoration the overdrive was operational. Nowit’s not. 
>The transmission andoverdrive have been taken apart and assembled twice looking for somethingvisually wrong. Everything seemed to be OK.
>The clutch and platewere also removed for inspection. The clutch was recently redone, adjusted andtested.
>A friend suggested weshould verify the oil pressure on the overdrive. On this link you will find acouple of videos of a test we have recently done with a manometer installed onthe overdrive to check the oil pressure at different RPM´s. 
>The pressure on 3rd and 4th gears goes upto 400 psi and drops as it goes to lower gears. At idle is between 150 to 200psi
>In forward gears thecar runs fine; the problem that we need to solve is that the overdrive would notactivate(even though it is connected and everything seems visually OK) and theslippage we have when engaging reverse (the car won´t move) when the engine /transmission is warm.
>We are located inLima – Peru and as you may imagine, there are not many experts in thisparticular area of expertise.
>Any thoughts or suggestionsfrom you collective knowledge and wisdom on how to proceed will be muchappreciated. 
>Thanks in advance!

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