ab1
From what I hear these aren't the most reliable things mines just being rebuilt Ive never used one before so I want to make it last.
1971_144GL
I am a believer in the penrite product for overdrive gearbox survival rather than automatic transmission fluid. It takes a little bit to warm up, but then is much smoother. I have used it with m41, and plan to do the same with my upcoming m41 and m410 projects. I did a technical project with penrite a few years back, and their chemists took their jobs very seriously to avoid selling junk.
Vee_Que
An m410 will last forever as long as the overdrive doesn't get killed by being engaged in the wrong gear. Or putting too much power through them.
ab1
So its really a cruising gear no acceleration or deceleration should be put through it. I thought the theres a solenoid that disengages it when shifted out of 4th
tbro
Alex, use the clutch when engaging O/D and when disengaging it. Same as changing any gears, do that and they should outlast the car.
ab1
Will do cheers!