4.5 slipping out of gear

Dan Suskin · Joined: 22 Feb 2011 Posts: 298 Location: Georgia, USA

On a wonderful tour in the North Georgia mountains in my 4.5, I had several occasions where the gearbox would come out of 3rd gear to neutral while running under load up a mountain.

I've checked the oil level - it is halfway up the layshaft as required, and I'm using Redline MT90.

On a Ghost, the gate at the gearbox lever prevents this from happening.

Questions:

1.) what prevents slipping out of gear here? Is it just the ball and spring?
2.) am I better off with a different oil?
3.) Can I remove the ball and spring with the gearbox in the car?

Many thanks

Chris Card · Guest

Technical Facts suggests that it is most likely caused by a broken or jammed selector ball spring or the gear lever gate may have shifted and limited the travel of the gear lever.
I suppose a badly worn gear could also cause it, but gear boxes are a mystery to me.

Chris

Dan Suskin · Joined: 22 Feb 2011 Posts: 298 Location: Georgia, USA

Thanks Chris. Assuming the spring is not broken, I'm going to increase the tension in the spring and see if that helps.

Chris Card · Guest

Let us know how you get on.

Chris

PS The selectors are made of a material that you cannot bend easily without them breaking, so be very cautious if you think of adjusting the shape of a selector.

Christopher Carnley · Posted: Thu May 17, 2018 2:00 pm Post subject:

All things being equal, increasing the tension on the spring may lead to coil binding and inability to select/disengage. Far better to increase the rating of the spring.
The selector shafts and detents are in the bottom, left of the casing.
It may be that the gravitational effect on the lever in 3rd speed is overcoming the spring load.

Dan Suskin · Joined: 22 Feb 2011 Posts: 298 Location: Georgia, USA

Agreed that a heavier spring might be a better choice, however adjustment is provided for in the threaded plug that holds the spring in place.

I’m not sure which way one references the gearbox, but the mechanism is in the front right of the gearbox as viewed from the driver’s position.

Dan Suskin · Joined: 22 Feb 2011 Posts: 298 Location: Georgia, USA

Follow up:

I stretched the spring that holds the ball in place - and it appears to have done the trick. I still need a really good, long mountain to climb, but so far, so good.

Chris Card · Guest

We'll keep our fingers crossed that you've fixed it.

Chris