Good Day Everyone,

I hope everyone's day is going well, I am in need of some guidance. I have an 2004 Lexus RX330 with 118k on it. Replaced both of the VSS sensors about 2 weeks ago. Since the replacement, the car often hesitates when shifting from 2nd to 3rd and 3rd to 4th and so on. It very rarely does it from 1st to 2nd. I have put over 100 miles on it since the VSS replacement. Its strange though, if I give it moderate to full throttle it shifts better. I have done the following troubleshooting but to no avail.
1. Pulled the negative from the battery for almost 20 hours.
2. Checked fluid, it is still red, level is ok, last replacement at 60k, not sure why Lexus dealer did not replace during 90k service.
3. Had car at dealer today for troubleshooting, dealer reflashed transmission with 2 updates and issue still exists.
I was told by dealer that they do not know what is causing it but I need a new transmission. I am a little dissapointed with that answer from the dealer.
4. No CEL codes or lights present, dealer said no codes on transmission either.

I have done research as to what could be causing this but I don't want to just throw parts at it. The suggestions are change the trans fluid, change both differential fluids, and clean the MAF sensor. Has this issue occurred to anyone else? Also, what are the steps to cleaning the MAF sensor? And where is it located? Any help would be greatly appreciated.
Thank you.

Also, is there a transmission shop or Lexus repair shop that others recommend in the Washington DC area?
Thank you.

You mentioned the shop reflashed the ECU.
Did they RESET the ECM memory after the flash?
Failure to reset the ECM memory will result in continued ATM shifting complaints.

Shop probably suspects a weak transmission oil pump.
Without doing a hydraulic test with gauges, it'll be hard to tell and just a guess for them.

Other test YOU can do:
Stall speed test.
-- Fully apply the parking brake.
-- Keep your left foot pressed firmly on the brake pedal.
-- Start the engine.
-- Shift into the D position.
-- Press all the way down on the accelerator pedal with your right foot. (no more than 5 sec)
-- Quickly read the stall speed at this time.

Stall speed:
2WD: 2,100 +/-150 rpm
AWD: 2,550 +/-150 rpm

If your stall speed is higher than specs, its likely the line press is too low.

So throw in a new transmission as a hail mary??? lol

Here is the path...
VSS sensors >> Skid Control ECU >> Main ECM (reflashed/didn't work) >> Transmission

Can I ask what led to your diagnosis of the VSS sensors?
PS- Interested to see your results from ideas and tests from previous post- that looks like a really good test to do.

The car originally had a Po500 code, VSC, CEL, ABS and brake lights all on the dash and speedometer did not work. Checked code and verified with shop that the VSS was bad. Installed new VSS, cleared the codes and shift issue developed. Had a shop look at the transmission shifting issue and they said that the Transmission valve body is bad. I am thinking of getting a second opinion.

How would I check to see if the ECM memory was reset after the flash?

To me it sounds like the whoever installed the new sensor made some sort of mistake. I would start by having that checked out.

However, a bad valve-body is a totally plausible reason for the shifting issues you describe. It could also be a number of different shift solenoids. These things usually break or wear out by your mileage from abusive driving and neglecting to drop the in order to clean the magnet and replace the filter. Contact a different transmission shop and DO NOT tell them you have any issues with shifting off the bat. Say that all you need is for them to drop the transmission pan to replace the filter/ magnet clean like I mentioned above. Once they are inside ask them to inspect the solenoids and valve body but do not say you suspect something is worn out,

Hi Tszabo,
If you go to a Tranny shop you can guarantee they will sell you a transmission rebuild or valve body and neither of which are cheap so should be last resort.

Can I ask please what Part# did you replace the VSS sensors with and Where did you buy it???
>> There is a Warning in the shop manual to Use ONLY OEM Sensor.

I got them from Car Quest, they were original Toyota Aisin parts with the following part numbers 8941308010 and 8941308020. I verified the part number on the packages and made sure that they were in original Toyota bags. I did the replacement myself. The parts were just under $400. I love the car but am annoyed that I am having these issues at 118K.
Thank you

Perfect! I was kinda hoping for you that you got aftermarket parts off ebay causing your problems and your transmission is fine.
What I find very suspicious is your VSS failure then now this problems with not shifting properly.
Ok plz start over- why did you replace the VSS sensors was there a code before you replaced them and then took car to dealer?
Edit: I see where you added the P500 code sounds good to me.
Does it improve after the engine/trans is warmed up?

Probably a long shot and only the OP can confirm this.
Does the two VSS that was replaced look alike?
Maybe, just maybe, they swapped those two upon install.
Maybe it doesnt matter but why have 2 diff part #'s.

Not to say that this would fix your problem but since you stated it happened after the work was done, then its a possibility.

Hello, I think I may be able to help. I bought an 04 rx330 with transmission shifting problems that the dealer could not fix. The problem was that the transmission speed sensor located on top rear of the transmission was the wrong part. I bought a replacement speed sensor from lexus and it too was the wrong part. The correct part is green and has a longer metal sensor. When I put the proper one in it worked perfectly. The one I used was this.
https://www.autozone.com/engine-mana...5_20280_115446

I see where you added the P500 code to diagnose the VSS(I missed that) and looks legit to me so I'm thinking bad/incorrect/misplaced too since
the manual is insisting that only the correct "oem" sensor will work so it seems to be a very sensitive application-
even though previous poster had better success with after market. lol

PS- I am very much hoping for you it's something simple like this and you do not need a transmission.

Good Morning,

Thank you everyone for the assistance. When I installed the sensors, I put the green sensor on the top position of the transmission which from my understanding is under the airbox close to the engine and I placed the black sensor in the bottom position which is under the battery. At this point I probably should have had the dealer fix it. That's what I get for saving money. :-)