[mav238]

Let it drain well
Measure drained volume
Replace with exact volume
Warm to either 40c or 70c point
Check level and adjust

Tough part is getting gearbox temp for nonamg
display cluster
Could use long thin braid thermocouple thru gearbox dipstick tube for direct measurement

I don’t think the OP was thinking of doing it himself. He’s just asking if he should change the trans fluid, probably at some mechanic shop.