Gearbox will shift down, not up.

"I did rebuild my 750 with DRY piston rings and a lightly lubed skirt."

I did the same when I re-ringed my 850 early this year - it's the current practice of a lot of well-known engine builders and, as you noted, they have found that it breaks in the rings/walls almost immediately. I have to admit that even though the tranny is on the bike now and full of ATF, I woke up in the middle of the night wondering if I should drain it out and put in gear oil!

So maybe my cahones are a bit lacking as well...

But then again, a few folks here have used ATF for a lot of miles so maybe they are like the first few guys who tried the dry ring installation - just ahead of their time!

mike
the ATF should not be an issue if your not beating on the tranny real hard. all auto tranny's have gears and bushing's in them and lube is not an issue and even some manual tranny's use ATF. now the bad news is it could leak easier because it's lighter viscosity and will not handle the shock load as well as gear oil but the shearing action and lubrication is not a problem with ATF.

Mike
I would not use ATF in these old Gearboxes because it doesn’t contain any extreme pressure additives Mick Hemmings recommends EP 90 Dino gear oil or you could try Synthetic gear oils are readily available. here is one eg. http://www.redlineoil.com/product.aspx?pid=47&pcid=7
Either way it will be your dime. To replace all the gears on an experiment gets expensive. :shock: I would not try to reengineer what the engineer who built the gearbox recommends. That AMC Gearbox was introduced in the 50s and right up to todays date the recommended oil is still gear oil.
CNN

CanukNortonNut said:

Mike
I would not use ATF in these old Gearboxes because it doesn’t contain any extreme pressure additives Mick Hemmings recommends EP 90 Dino gear oil or you could try Synthetic gear oils are readily available. here is one eg. http://www.redlineoil.com/product.aspx?pid=47&pcid=7
Either way it will be your dime. To replace all the gears on an experiment gets expensive. :shock: I would not try to reengineer what the engineer who built the gearbox recommends. That AMC Gearbox was introduced in the 50s and right up to todays date the recommended oil is still gear oil.
CNN

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I second that. Quaife recommends synthetic gearbox oil for its classic gearboxes, which are essentially improved versions of that which we have in our Commandos. I wrote to their technical section and asked them to confirm this, which they did. If a gearbox manufacturer with an international reputation like Quaife advises this, then I would follow their advice. I would also fit a magnet to the gearbox drain plug.