Ok I recently posted a thread about my tranny malfunctioning. It's going into drive while the shifter is in reverse and neutral. I'm new to Lexus and just a little bit lost. I've read that bad tranny fluid can cause problems as well as improper fluid level. The car will drive forward but typically stays in first.
So I'm going to start going down the list of what my problem could be. And I'm starting with the fluid and trans filter, also replace the trans gasket. Apparently it's leaking bad. But I'm standing here at ad advance auto parts wondering what tranny fluid can I use. I see type f fluid which I've seen in some Toyotas also castrol transmax fluid, that state it good for Lexus vehicles using type t, t-III, t-IV. Also I see royal purple max ATF. Which one should I get?

 

Neither, go to the the dealer a get toyota atf IV ONLY. Trust me on this, these trannies are picky. Its only 2 bucks more per quart than the instore brands.

 

Yup. This.

You can also buy Mobil 3309 but just go to the dealership and get Toyota ATF IV.

 

Yup only oem type ti-v.

 

Ok so I found the oem trans fluid. Changed the filter, installed a new gasket and poured 3 quarts back in the system. Now instead of going forward in reverse, the car just sits there as if it was in neutral. Driving it was very smooth for the most part. But it still drives forward in neutral. I have no signs of a solenoid problem right. There's also no check engine light or warning signs.

 

Sounds like it is most likely time for a rebuild.

 

This. ^^ .......................................

 

Ok which is more cost effective. Just replacing the trans, or rebuilding it? Or the 5spd swap?

 

replacement is cheap for a good used one usually under 500