I have a '93 F150 4x4 with AOD transmission and 108k miles on it. Transmission fluid/filter has never been changed. Should I change fluid/filter with this high mileage or let it go? Fluid is still red and smells O.K.! Wouldn't want to break loose some crud in there and and have problems. 'Mo

 

Exact same situation as you with the '88s AOD with 106k. I'm gonna leave it alone, unless it starts acting up.

Adrianspeeder

 

I'd change it & the filter, using some cheap Dexron III. After ~500 miles, change it again using Motorcraft Mercon Multi-Purpose (not V, not F, not Synthetic).

I'd also add an aftermarket drain plug kit.

 

If the fluid still looks good, go ahead and change it.