If the transmission is spotless clean I would have no problem running ARX in the transmission for much longer than the 1000 miles. But the only way to verify a spotless tranny is to tear down. So in reality I advise that the stock instructions is the way to go.
Though I suspect auto transmissions are mainly referred to here, I was wondering the same with respect to manual gearboxes. I just started an ARX treatment in my '95 Civic manual tranny with 103,884 miles upon adding it, and considering the incredibly great results I've had with Auto-Rx in my engine the thought naturally occurred to run some sort of ARX dosage for maintenance purposes in the little tin-can wonder's gearbox... Not that I'm tough on it which I'm not... (sorry if this is threadjacking)
I have no doubt the trans is fairly clean right now and will be as clean as possible after the ARX treatment. In fact I may possibly run this treatment beyond 1,000 miles because of my confidence in its current condition and the fact that I know the Auto-Rx will not hurt it one iota. And there's also the possibility I won't be able to change it out at 1,000 miles...
I am a solid believer in this stuff- testimony #80 is mine.
manual transmission is the least likely to get dirty, they run much cooler, burned fluid, grit etc..., where is it going to come from? I suppose if you got some water in there it could corrode. But I have never seen them be dirty inside.
engines get dirty from burning fuel, acid contamination water sludge grit from the air, automatics have issues with very hot or burned fluid and clutch material debris, leaky worn rubber seals. I can see this product helping with that.
