[Healeys] When to change transmission oil

[Ron Fine]

I have Redline MT-90 in my transmission (BN7) which was completely rebuilt in
2005.  The oil is about 5 years old.  I drive less than 2000 miles a year.
Transmission runs fine.  Is there a consensus or guide line on how often to
change the oil?

Thanks,

Ron Fine
61BN7
W.L.A.