macgy

i bought a used RX300, just recently, the transmission is acting up, while cruising on the highway, the gear downshift for no reasons, this has happens a few time to be concern. when i slow down to about 5km/h, a hard push on the accelerator doesn't produce a downshift to speed off. acceleration from the start and gear changing is excellent though, no slip. i have replace the g/b oil but problem remain unsolved.
A symptom of gearbox failure i guess, but b4 i spend my hard earn $ for a replacement g/b, m thinking of flushing the g/b and replacing the g/b oil to redline ATF or just add a bottle of lubeguard g/b additive and hopefully it will clean up any blocked valve?, anybody has done this before? does it help?

thomas1

Dont flush, drain and fill and replace the filter assembly, than drive for a week and do the same again with a drain and fill. good luck..

HarrierAWD

I'd suggest doing 3 ATF drain-n-fill and see if things improve.

Lexmex

Welcome to CL.

Disconnect your battery and then reconnect it.

Also follow the advice of the thomas1 and HarrierAWD, drain and fill it two more times and change out the filter and let me know what color the fluid looks like right now and what it smells like.

https://www.clublexus.com/forums/sho...d.php?t=220061

TunedRX300 did a very good job of showing how to do the drain and fill along with changing out the filter.

I'd be interested to know what is in the bottom of your transmission pan on the magnets.

macgy

alright no flush, i ve drain the ATF once again, ATF looks new and no burning smell, replaced the ATF, filter. No significant improvement so far. i ll repeat the procedure next week n keep you guys update, thanks for reply.

lexxyman20

O kay, I am that soldier and sitting right where you are only i seem to have lost reverse gear also, i hve got to the stage now where im in the middle of trying to drop the transmission out, but as i see the engine and transmission must have to drop together, im searching breakers for a second hand transmission but of course there are three different types, so ive been told to take my old one with me as i cant seem to find the correct number on the box, any one who has done this repair id dearly like to hear from you,
Many Thanks
Lexxyman20

Lexmex

Welcome to the club.

It would help to know what year you have and whether you have an AWD or FWD.

The transmission mated to the FWD RX300 is the U140E, while for the AWD RX300 it is the U140F.

The transmission can drop out separately from the engine, https://www.clublexus.com/forums/rx-...went-bump.html