[Boots]

I'm no authority on this but the following is how I drive the OD and it seems happy enough!

You shouldn't depress the clutch when selecting or de-selecting the OD, it has its own 'clutch' internally.

The main gearbox should have a switch that only allows the OD to be selected in 4th gear and automatically de-selects it if you move the gear lever out of that gear. (700/900 only???)

When selecting or de-selecting the OD, momentarily lift the throttle to the point where the engine is no longer accelerating or braking so that there is minimum strain on the drivetrain whilst the OD engages/dis-engages. Then re-apply throttle or release completely depending on whether you desire acceleration or engine braking.

The throttle action you want is pretty much identical to that which you would perform changing between gears in the main box, except there is a short delay between pressing the button and when you need to lift your right foot.

I find this delay depends on road speed. At 30mph it can be nearly 1.5 seconds. When thrashing flat out at 70mph the whole sequence from pressing the button to getting back on the throttle takes less than half a second.

At low road speeds (below 40 mph say) with the engine braking, I feel that the forces involved are low enough to not touch the throttle at all when de-selecting the OD. It just gently disengages, the revs rise a bit and you get some more engine braking.

Once you get the hang of where to put the throttle when, you can get the changes so smooth your passengers won't even know they've happened.

Have you ever tried changing up and down a manual box without using the clutch? If so, you'll know what I mean by 'matching' the revs. This is what you want to be doing to give your OD an easy life...

Although the 4th gear switch will dis-engage the OD when you shift down, I don't usually rely on this as, on my box, going straight for 3rd from 4th + OD catches the synchromesh on 3rd out, eliciting a fairly good crunch! If I know I'm gonna want 3rd next (approaching roundabout/traffic etc.) I de-select the OD a couple of seconds before changing down.

All this said, I get the impression that this OD is a pretty sturdy beast and will stand up to a fair amount of abuse. I occasionally have brain fade and press the button at silly times or forget to lift off the gas and it seems to survive!

Now I've got used to it, I really love my OD - its really satisfying when you get it just right...