Originally Posted by TimMullen
I haven't changed the gear oil in my Elise yet, but using the Miata as a typical example, the transmission holds a tad bit over 2 quarts. After draining, you can put back in 2 oz. less than the "dry" capacity. 2 oz. out of 2 quarts is nothing - that amount won't hurt anything and doesn't need "flushing". Also, consider that the vast majority of cars out there never get their gear oil changed, and yet still manage to last a couple of hundred thousand miles.
But if you want to drain, refill, drain again, and refill again - go ahead. It won't hurt anything but your wallet.
The Elise takes 2.4 quarts and unless you know how
to buy Trany fluid that matches this exact amount
of fluid, you'r going to have 0.6 quarts left over.
How does using that amount, which you will no longer
have any use for, affect anyone's wallet? As far as cars
having never had their gear oil changed over a lifetime
that can reach 'a couple of hundred thousand miles', why
then does Lotus tell you to change it at 45,000 miles?
Newer fluid works better in the abraisive, high temperature
environment it is subjected to, than older fluid. And I
repeat that simple draining leaves old fluid in the trany
which costs you nothing extra to extricate, using the
'left over' new fluid from the three quarts you have to buy
anyway. But if you like leaving fluid in for hundreds of
thousands of miles, which flys in the face of what Lotus
recommends, go ahead.