I'm about to change the gearbox in my van. The markings on the box I'm about to put in are,
On top ZL in large letters painted in yellow
Right side HOLDEN 10 9938391
Left side 29LS 7 HOLDEN
Front HOLDEN 9930912
The original box in the van at the moment is a M20. Is this a M20 or M21. Can you even tell from the outside?