Popping Out Of 3rd Gear

[Cal]

On the way to the Nats my gearbox started popping out of 3rd gear. it mainly happens if its under load (like going up a hill) and when its very bumpy. Gets a bit hairy when your driving up a hill with some feral truck right up your arse, and the thing just pops out of gear If I rest my hand on the gearstick, it stays in gear.

Is it a linkage issue, or is the gearbox rooted?. I'm dreading the drive back to Sydney

[gp]

Hi Cal,
This is a reasonably common problem (It's more common with the EJ-HR style crash boxes).

First things to check are whether the gearbox bolts are tight (bellhousing to engine block).

Then check the adjustment to make sure that it's going into gear properly (i.e. make sure it's not half in gear).

To go a bit further you might need to delve into the selectors & stretch the springs on top of the balls on the selector shafts (I hope that makes sense??)

Sometimes the problem is actually caused because the gearbox case has stretched, which leaves too much clearance betwenn the input shaft & mainshaft, allowing it to "slip" out of gear.

I think that there was a service bulletin issued about this problem (Maybe someone else on the forum can confirm this?)

Worst case is that it will need a rebuild.

I hope this helps.......

Cheers, Graham

[Harv]

Easy fix... just hang a handbag on the gear lever . Or for the more masculine, an occy strap. Both genuine NASCO accessories (like the wooden bonnet holder-upper). See page 99 or so:
http://www.fbekholden.com/forum/viewtop ... 26&t=18606

The detent springs can be a mongrel to stretch as they are quite stiff... tend to deform sideways before they stretch. One other way is to add collets (washers) between the spring top and the set-screw. This pre-compresses the spring, making it harder for the selector shafts to jump the detent notches.

When checking the gearbox for tight bolts, make sure they are retightened in a cross-fashion not round-the-circle). Sounds finnicky, but can help prevent warping the casing.

Cheers,
Harv

[Aussie Bob]

I would also check your engine mounts!

Have fun at the NATS.

Steve

[Cal]

Thanks fella's, I'll check it all out.

Someone else did say engine mounts too Steve. Makes some sense if it happens under load .

I'll limp it back to Sydney (with the handbag ) and sus it all out

[bootlegger]

Pete its pretty easy to check if its the engine mounts. With someone looking under the bonnet try driving the car forward in gear while holding the brake on. The engine will twist. If the gearbox mount is buggered you will see the engine try and climb out.
Its usually the mount on the passenger side that goes.

[postman_warren]

hello recently had my gearbox overhauled the old mechanic told me his father worked at freeman motors and one of gmh technical bulletin spoke the issue of warped bell housing can cause problems with the speed box one of which is jumping out of third gear . warren