Help - "R" Reverse gear does not work
10-21-09, 08:54 PM
#16
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Not sure how the sensors were tested, will ask mechanic. The reverse problem involved putting it in reverse, press gas, car doesn't move, just revs. Keep trying, and suddenly it jerks and responds. Transmission problem was pressing gas and car not accelerating. In contact with my local Lexus dealer to see what they can do since car was always serviced at Lexus, and the reverse problem started months ago but Lexus said they couldn't find a problem and couldn't replicate it. Reverse problem only happened about once a week. We had to rent a truck and auto carrier and tow it back home since it broke down on vacation. Bummer. Have an Olds minivan with the same miles...it works fine and my Lexus is in deep trouble...something not right about that.
10-22-09, 07:09 AM
#17
Lexus Test Driver
That's exactally how my trans problem started. About once a week I had the reverse problem. I pulled the sensors cleaned them and reinstalled. I also swapped their positions thinking that if one was bad I would end up with another problem other than reverse. This definetly fixed the problem. The car went for months without any reverse issues, when before it was happening once a week. But finally the trans failed. What I suspect happened here is the planatary gear in the trans started to fail and caused a lot of "metallic fuzz" in the fluid. This sticks to the magnetic sensors and causes the reverse issue by giving false readings. The sensors will test good but are giving false readings. Cleaning the sensors will fix the reverse issue but the long term problem is still there. I don't think there is any point in checking the sensors other than swapping and cleaning them. They are checked by the ECU and will give a OBDII code and a CEL if they are bad.
11-30-14, 04:07 PM
#18
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I would be reluctant to call Lexus or Toyota. Due to the history of trans failures on the RX will get the standard short answer that you need a trans for about 4 or 5 k. A trans shop will most likely want to tow it in to diagnose and then tell you you need a trans for anywhere from about 2K to about 4.5K. And you may very well need a trans but there are a number of things you can try first which may fix the problem.
I know you said that you can't push it in neutral, but when you put it in reverse does the engine bog down a little like something is locked up or does the engine just rev like there is no connection from the engine to the drive wheels?
I would first try disconnecting the negative battery terminal for a few minutes to reset everything. This is a long shot but it is the easiest to try.
There have been 3 or 4 other instances of owners with the reverse problem (myself included) and we were able to fix the problem by cleaning the speed sensors. Cleaning the speed sensors is no harder than an oil change, maybe easier. So, if you can change your own oil you should have no problem. If not grab a friend who can. Here is a link with a picture of a trans. The speed sensor is black plastic and is on the right. It is held in by a 12mm bolt. In the post just below the pic I have some basic directions.
https://www.clublexus.com/forums/sho...=speed+sensors
I know you said that you can't push it in neutral, but when you put it in reverse does the engine bog down a little like something is locked up or does the engine just rev like there is no connection from the engine to the drive wheels?
I would first try disconnecting the negative battery terminal for a few minutes to reset everything. This is a long shot but it is the easiest to try.
There have been 3 or 4 other instances of owners with the reverse problem (myself included) and we were able to fix the problem by cleaning the speed sensors. Cleaning the speed sensors is no harder than an oil change, maybe easier. So, if you can change your own oil you should have no problem. If not grab a friend who can. Here is a link with a picture of a trans. The speed sensor is black plastic and is on the right. It is held in by a 12mm bolt. In the post just below the pic I have some basic directions.
https://www.clublexus.com/forums/sho...=speed+sensors
04-09-15, 09:09 PM
#19
Lexus Test Driver
I know...old thread
But the old ones are sometimes the most useful!
Tuesday, my wife got home, came in, changed clothes, and needed to go back out and run a couple of errands.
I hear Princess's horn toot from the garage...I wonder what's up. Get to the door to the garage, open it, and my wife has the windows down and says Princess won't move.
?!?!?!?!
Lemme check that. Sure enough, reverse = nothing. Drive, you can go forward, but it's in the garage, this is a problem.
Couldn't even get her to move in neutral or reverse, engine off. It was like 'park' was engaged in anything other than "D".
Pulled the sensors, gently, cleaned them with a paper towel (they had a dusting of metal on them...barely...only 130K miles on her), put them back, put everything back, and sure enough, she's just fine, now.
This is really odd.
Tuesday, my wife got home, came in, changed clothes, and needed to go back out and run a couple of errands.
I hear Princess's horn toot from the garage...I wonder what's up. Get to the door to the garage, open it, and my wife has the windows down and says Princess won't move.
?!?!?!?!
Lemme check that. Sure enough, reverse = nothing. Drive, you can go forward, but it's in the garage, this is a problem.
Couldn't even get her to move in neutral or reverse, engine off. It was like 'park' was engaged in anything other than "D".
Pulled the sensors, gently, cleaned them with a paper towel (they had a dusting of metal on them...barely...only 130K miles on her), put them back, put everything back, and sure enough, she's just fine, now.
This is really odd.
04-10-15, 06:18 AM
#20
Lexus Test Driver
But the old ones are sometimes the most useful!
Tuesday, my wife got home, came in, changed clothes, and needed to go back out and run a couple of errands.
I hear Princess's horn toot from the garage...I wonder what's up. Get to the door to the garage, open it, and my wife has the windows down and says Princess won't move.
?!?!?!?!
Lemme check that. Sure enough, reverse = nothing. Drive, you can go forward, but it's in the garage, this is a problem.
Couldn't even get her to move in neutral or reverse, engine off. It was like 'park' was engaged in anything other than "D".
Pulled the sensors, gently, cleaned them with a paper towel (they had a dusting of metal on them...barely...only 130K miles on her), put them back, put everything back, and sure enough, she's just fine, now.
This is really odd.
Tuesday, my wife got home, came in, changed clothes, and needed to go back out and run a couple of errands.
I hear Princess's horn toot from the garage...I wonder what's up. Get to the door to the garage, open it, and my wife has the windows down and says Princess won't move.
?!?!?!?!
Lemme check that. Sure enough, reverse = nothing. Drive, you can go forward, but it's in the garage, this is a problem.
Couldn't even get her to move in neutral or reverse, engine off. It was like 'park' was engaged in anything other than "D".
Pulled the sensors, gently, cleaned them with a paper towel (they had a dusting of metal on them...barely...only 130K miles on her), put them back, put everything back, and sure enough, she's just fine, now.
This is really odd.
Most failures start off like this. You can do a couple of drain and fills to try and prolong it. Some go for thousands of miles after this, others not so much.
04-10-15, 09:02 AM
#21
Lexus Test Driver
We'll see.
It's had fluid changed every 20K-30K, isn't abused, and shifts just fine.
I can see how, over time a metallic "dust" gets on the sensors and impedes what they can sense.
I'll letcha know.
It's had fluid changed every 20K-30K, isn't abused, and shifts just fine.
I can see how, over time a metallic "dust" gets on the sensors and impedes what they can sense.
I'll letcha know.
04-10-15, 09:09 AM
#22
Glad the problem went away but it seems coincidental.
EDIT: I was thinking the abs sensors which are sometimes referred to as speed sensors in other context. The speed sensors on the transmission also appear basic unless there is some logic built into the circuitry for a lockout. otherwise it still looks coincidental.
Last edited by fastnoypi; 04-10-15 at 06:52 PM.
04-10-15, 06:02 PM
#23
Lexus Test Driver
I'm with you, it can't be due to this. I mean, the whole parking pawl thing is still 100% mechanical, isn't it? If it weren't, should the battery die, you can't take it out of gear.
04-17-15, 03:56 AM
#25
Lexus Test Driver
To remove said air box, you need a Phillips screwdriver (for the intake tube), and a 10mm socket with either a decently long extension or a stubby ratchet to remove the three bolts at the bottom of said housing.
The sensors are press-fit, but retained by I think a 12mm bolt. Now, they use O-rings to seal, so to remove them, you have to be firm, but gentle. Using a twisting motion as you pull on them WITH YOUR FINGERS, helps. Remember, the sensors are plastic, and they're in a harsh environment, so they'll be brittle.
There's a link in a post, above: https://www.clublexus.com/forums/rx-...nsmission.html
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