He meant your automatic transmission unlocked while going through the gears.
I would do it, no matter how many miles are on the transmission it is only a matter of time before it pukes, some have had trouble with low miles and power upgrades some have had trouble with high miles and upgrades, so it is a matter of preference with a dash of the transmission will need fixing sooner or later, depends if you want the sooner or later as any upgrade will compromise the weekest link in any system.
Ron