Just happen yesterday, some help would be great
 

My brothers rx300 all of suden lost power and the gears will not shift and the rpm just goes up. THe check engine light came on saying shift solinoid problem or something like that. What should he do? Is it a sensor or something worse? would a tranny flush fix the problem?

Check the fluid condition by the dip stick. If the fluid is not clear then at minimum drain and fill or remove the pan and replace/clean the filter is required.

Need to share the history .. specially what has been done to the transmission, including fluid change(s) and at what milage and when.

Next is what you want done and how. If you are going to let the dealer or independent shop handle it, then I would suggest take it to them.

If you want to DIY then start by replacing the bad sensor. In the process you may have to drain the fluid.

I would stay away from flush. But if the transmission is replaced then do ask for flush of lines as well as change the rear main seal of the engine.

Salim

he bought the car from a dealer
 

someone traded it in, I will let him know, by the way how much is the sensor going to cost and if any link of which one would be great.

Post the code and or sensor name.

search the net for the part or even call up local Lexus parts.

Salim

The shift solenoid code is common when the transmission fails...I would do as Salimshah says and go from that point...A flush will not fix it...dont bother. Do a drain and replace the tranny filter..inspect the pan for metal debris. Good luck

SO after the drain which oil do you recommend
 

to put back into the tranny? I bet the dealer knew of this issue and sold him a lemon, but it happen after like 8000 miles :( pure bad luck I guess. SO the drain can you please explain how that helps?? If there are metal debris just remove them or does that mean those are gear parts?

There are a few DIY's on here which explain how to do a drain and fill. Debris are normal all cars have debris but obviously there is a limit to everything. Make you sure you fill it with Toyota Type-IV fluid.

Never!. Do not reuse the fluid.
The sensor can go bad and typically it is immersed in fluid and any thing floating in fluid can deposit on the sensor.
My recommendation was to check the condition through dip-stick pull, before taking any steps.
There is no chemical injection in the transmission fluid. If there is a change it is due to heat and wear of parts (gears and bands etc). Thomas is our resident expert in transmissions and photos posted show a gray powdered coating in bad transmission (seem like a gear disintegrated) and carried all over by the transmission fluid.
But all this could be an over-reaction. Go through the steps

1. Check fluid. Replace if needed. Drop-pan if needed.
2. Check/replace sensor

Salim
Countdown 10, 9, 8

Here is posting for changing filter and fluid:
https://www.clublexus.com/forums/rx-...er-change.html

Please note when pan is removed and if (I hope not) you find lots of metal debris than the planetary gear assembly probably gave up....If you dont have the debris than changing the shift solenoid and filter and new fluid may get you going again..Good luck

If it were my car I would take it to a dealer first, then take it to a private transmission place. If they both agree on the solution, I would take the less expensive private route.

Carl