its a feature of this appliance build that when the engine revs die and the driver just catches it before it stalls, then there can be a compression backload and the engine can fire in revers - so exhaust coming out the air filter,, 6 reverse 1 forwards gears...lol, the CFA mechanic was trying not to laugh when he told us. To fix just switch it of, and start it again.
This build is pretty good, spoiled by the fact that it only seats 5, theres a dinky rubber underbody hose reel (just like all the Hino 34s) on the ones I saw, and theres lots of lockers underneath the appliance to catch and snag on obstructions. Body locker space is limited. The Maffra appliance had taken a battering on one of its underbody lockers when we were there. One of the versions that was there had 3700l of water, which was interesting.
Interesting to see the different builds of the same appliance between Varley and SEM. Also interesting to see the latest version from Grange CFA with a front remote controlled monitor