I wanna drain my transmission fluid, but I don’t know what’s recommended i’m at 170k miles. Also, not sure what additives i can use to prevent slipping.

 

Few months ago I REPLACED my ATF for the first time ever: 105K miles. I used the very expensive AMSOIL - Signature Series. As a once in a decade maintenance step, I went big. I also dropped the pan, replaced the trans filter. More importantly, I did not mix 18 year old burnt out fluid with the new stuff. Draining your fluid will only eliminate 4-5 QTS out of 9 QT capacity because 1/2 of it is sits in the torque converter and trans lines. Unacceptable. I performed a controversial fluid flush like the one in this YouTube video:

You Tube

I was able to replace 95% of the fluid using this technique. It's been 5 mos. and my transmission shifts through all gears like butter.

 

Castrol Transmax High Mileage ATF

Castrol Transmax Full Synthetic Import Multi-Vehicle ATF <--- I use this

Amsoil Signature Series Multi-Vehicle Synthetic Automatic Transmission Fluid

Amsoil OE Multi-Vehicle Synthetic Automatic Transmission Fluid <--- I use this too

Idemitsu ATF Type HP <--- I use their CVT fluid

 

I can highly recommend Valvoline Maxlife, about $25 for a 5L (1 Gal) jug at Walmart.
BTW, it's more important to change it frequently then to agonize over which fluid to choose. I drain&fill every 15K miles (be aware that in one drain&fill you only change about 1/3 of the total).