Had my transmission rebuilt on my ‘04 Ford Explorer XLT 4L about 3 years ago at 140K miles, currently have 159K miles and am wondering should I change the transmission fluid and filter or just the fluid now? I want the transmission to last at least another 100K miles.

 

You only have 19k miles on the fluid. I would wait till you get around 30k miles on your rebuild and then do a fluid change with a filter. You might want to upgrade your pan with a drain plug at that time as well..Go by mileage, not time.

You might want to get your Mercon V now because I am sure it will be pretty expensive by then.