Trans fluid

Was changing my diff fluid today and noticed my pilot bushing (I think) was leaking some trans fluid. Let the truck warm up for a while and drove around for 5-10 minutes, checked the fluid and it was low. Below the cold mark. I’d like to top it off with some new fluid before I get it into a shop to get taken care of. The problem is I’m not sure what trans fluid is in there since I just bought the truck. Can I mix different fluids? Would anything go wrong if I put in some valvoline dex/merc in but the old fluid is Toyota t4? Sorry if it’s a stupid question, just don’t wanna play around with the transmission. Thanks for any input. Truck is 98 sr5 4x4 automatic

 

Look at the dipstick. It should be on there. Toyota ATF dipsticks are stamped with the fluid they take.

if checking only, start at step c4
https://www.tacomaworld.com/threads/high-mileage-2002-prerunner-diff-oil-trans.833159/#post-29857418

 

My understanding:
4cyl = TIV
6cyl = Dex

If the atf drain bolt is original, it will be stamp which type of fluid. If it’s calling for TIV, I wouldn’t add the blue bottle Val Dex/Merc, I would use the red bottle Maxlife.