Hi Scotty,
Should I change the transmission oil and the differential oil on my recently purchased 2008 Honda Element LX AWD with 230k miles on it? I dont know if the last two owners were maintaining the car properly but I am planning to take a good care of the car to make it last.
Thank you.
See the site FAQ entry on changing transmission fluid.
Before I go ahead and change the fluid, I want to know if it is safe to do so and no bad things would happen.
No one can predict what will happen with old and possibly poorly-maintained transmission.
As I said, read the FAQ, the issue is covered there in detail. If your differential is separate from the transmission, its fluid (which would probably be gear oil) can be changed with no problem. That information would be in your owners manual, which would be available online if you don't have it.