Temperamental overdrive

[Fordski]

No doubt a hardy perennial but the overdrive is playing up! Runs fine initially but after a while tends to drop out of 4th, and there is also a stranger 'fluttering' or clicking sound when it is engaged in 4th once speed increases to 50mph +. I think it is something to do with the OD as it doesn't make this noise when its not engaged. I guess it is something to do with the solenoid and whilst I'm getting it checked out on Monday any thoughts welcome.

I report back anyway hopefully when it is fixed.

Fordski  

[Richard B]

Clicking sound is usually the relay tripping in (and out).

I would check the wiring. Does it have a gearstick switch, the wiring there is often the culprit.

[Fordski]

It's a steering column switch, but sounds like a good place to start.

[Pete Lewis]

firstly do you know what model overdrive is fitted,
D type solenoid on drivers side
J type passenger side

most common is the D type,
with any OD always check the gearbox oil level is up to the level filler ( plug on o/s front of gearbox.)  the oil is common to both chambers

aged broken wiring due to heat is common, especially around the inhibitor switch on the top of the gearbox.
If its a D type , remove the os side cover and energise the solenoid, inside the cover is a short lever , pulled by the solenoid, in this lever is a 3mm hole, use a drill as a gauge it should pull the lever till the hole aligns with a drilling in the case behind the lever,  if this is incorrect you can carefully adjust the solenoid rod nut to get things inline,

if it was wired up though a hollow gear stick to a gear knob integral swicth , this suffers from wire degradation and thats where to start, yours does have that problem being column mounted .

if you have an ammeter handy the D type pulls around 10amps as an initial pull, once the solenoid has pulled in there is a sealed switch in the end of the solenoid which cuts the current to a holding 0.5amps..    hence any poor connections can hamper the  few second burst of 10amp pull in

Pete
  

[Fordski]

Pete,

Thanks for the comprehensive reply. I'll have a look tomorrow.

Andy F

[BAC]

Mine used to do that, I have the D-type. The sprung pin on the switch bolted to the side of the gearbox was really worn. so much so that if I kept pressure on the lever with my knee it was fine, move the pressure off and it was click click click. A new switch for less than a tenner and about 20 mins work fixed it.

[junkuser]

Could low oil level cause this?

[GT6 M]

Only if  going doon a hill Mal, as oil runs frae OD to GB.
going up hill its ok thou

M

[junkuser]

Thanks Marcus,
Mal.

[Pete Lewis]

if  D Type and, all else fails take out the top spool valve plug, remove the short hollow needle/valve pin and check the tiny hole through it is fully clear

any debris inside will drop the pressure and erratic operation persists

Pete

[Fordski]

It seemed the solenoid needed 'resetting' or aligning as you suggest in your earlier post Pete. All working OK now - touch wood. Thanks for the helpful responses. Until the next time TTFN.