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duke39

Rx300 Transmission Problem

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Hello,

I'm a first time poster to the forum. I have a 99 RX300, fwd, 128K.

I have just recently experience a problem of not being able to shift from 3rd to 4th gear. After getting to 40 mph, it appears that there's no up shifting for any speed higher. The RPM at 60 mph is around 3K, and 70 mph is around 4K.

I checked my fluids (oil and transmission) and they appear to be in line. I don't know if this is the beginning signs of a transmission overhaul. I'm planning to take it to nearby shop next week, but would appreciate it if anyone has any insight or has experienced a similar upshifting problems.

Thank you in advance. My apologies if this topic has been covered in a past thread.

Best,

Can

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Does this occur all the time or just when you are starting out? The engine has to reach a certain temp. before the transmission will shift into overdrive.

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Does this occur all the time or just when you are starting out? The engine has to reach a certain temp. before the transmission will shift into overdrive.

The problem started about a week ago, only occasionally and not during every driving session. It would occur after I come to a stop and then try accelerate to 40 + mph. When I first noticed the problem, I would pull over and turn off/on the engine and the shifting would resume as normal.

But lately, the problem has been consistent at starting and after I begin driving.

-Thanks

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Does this occur all the time or just when you are starting out? The engine has to reach a certain temp. before the transmission will shift into overdrive.

The problem started about a week ago, only occasionally and not during every driving session. It would occur after I come to a stop and then try accelerate to 40 + mph. When I first noticed the problem, I would pull over and turn off/on the engine and the shifting would resume as normal.

But lately, the problem has been consistent at starting and after I begin driving.

-Thanks

Assuming no CEL or other diagnostic indication your engine may have simply degraded to the point wherein 4th(OD) can no longer be supported.

Miles..??

As a test I would disconnect the battery for about 10 minutes to reset the system's "learned" parameters. If the OD then works for a short period or time then "learns" not to use OD again then you likely need an engine overhaul.

You might also try a FULL tank of premium fuel to help bring the engine back into the required OD RPM/torque range

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Assuming no CEL or other diagnostic indication your engine may have simply degraded to the point wherein 4th(OD) can no longer be supported.

Miles..??

He mentioned 128K miles. That seems kinda low for a quality engine to be that degraded. Or, at least I hope so as mine isn't too far behind it in miles.

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Possibly your neutral safety switch is going bad. To confirm, start the engine, step firmly on your brake, and change gears back and forth numerous times to clear the contact in the neutral safety switch. If it helps your problem, you need to replace the switch soon.

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Possibly your neutral safety switch is going bad. To confirm, start the engine, step firmly on your brake, and change gears back and forth numerous times to clear the contact in the neutral safety switch. If it helps your problem, you need to replace the switch soon.

tta300,

I did as you mentioned and it works! Before I shifted through the gears, I tried driving it and the problem persisted. I then parked and shifted through the gears, and then resume driving with shifting success.

I'll check with auto shops to see how much it is to replace the neutral safety switch.

Thanks for your help.

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A Toyota dealer can replace the part for you at reasonable cost, and get it done right for the 1st time. Since you are there, you may ask them to drain and refill 4 quarts of Toyota Type4 transmission fluid to improve shifting. If I were you, I would not count on advice from any other garage or local transmission shop for engine/transmission related issues. Good luck!

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Hello Can,

I have the exact same problem, I wonder what it was in your case! How did you fix it. I took to the repair shop they said it tranmission and need to replace and after they rebuilt the problem seems never fixed. Please let me know or email me at nguocphong@gmail.com. It cost me too much money but the problem never fixed!

thank you,

nguoc phong

Hello,

I'm a first time poster to the forum. I have a 99 RX300, fwd, 128K.

I have just recently experience a problem of not being able to shift from 3rd to 4th gear. After getting to 40 mph, it appears that there's no up shifting for any speed higher. The RPM at 60 mph is around 3K, and 70 mph is around 4K.

I checked my fluids (oil and transmission) and they appear to be in line. I don't know if this is the beginning signs of a transmission overhaul. I'm planning to take it to nearby shop next week, but would appreciate it if anyone has any insight or has experienced a similar upshifting problems.

Thank you in advance. My apologies if this topic has been covered in a past thread.

Best,

Can

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Possibly your neutral safety switch is going bad. To confirm, start the engine, step firmly on your brake, and change gears back and forth numerous times to clear the contact in the neutral safety switch. If it helps your problem, you need to replace the switch soon.

can you elaborate on this switch?

ours has done this afew times then just goes away.

we're at 113k miles.

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Neutral Safety Switch or PNP Switch provides input signals to ECM to indicate shift lever position. The contacts inside get worn/corroded over time. It is located on the side of transmission, facing the front of the vehicle. You'll see it once you remove the battary and the air filter housing. The following is a picture link of a similar device.

http://catalog.autohausaz.com/autohausaz/i...20088503OES.JPG

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I had hard shifting and loss of overdrive gear on my 99RX with 175,000 miles on it and everyone was telling me it's time to rebuild the transmission for $5,000. I took it to some small transmission shop and the old guy there replaced a "speed sensor" and it works fine, better than ever. I also had him flush the transmission and replace the fluid, but the sensor was the real fix. I'm sure it could use rebuilding after this many miles, but I was thrilled to get by for $200 and still use it as a spare vehicle in the winter and other times.

Good luck,

Brian

Hello Can,

I have the exact same problem, I wonder what it was in your case! How did you fix it. I took to the repair shop they said it tranmission and need to replace and after they rebuilt the problem seems never fixed. Please let me know or email me at nguocphong@gmail.com. It cost me too much money but the problem never fixed!

thank you,

nguoc phong

Hello,

I'm a first time poster to the forum. I have a 99 RX300, fwd, 128K.

I have just recently experience a problem of not being able to shift from 3rd to 4th gear. After getting to 40 mph, it appears that there's no up shifting for any speed higher. The RPM at 60 mph is around 3K, and 70 mph is around 4K.

I checked my fluids (oil and transmission) and they appear to be in line. I don't know if this is the beginning signs of a transmission overhaul. I'm planning to take it to nearby shop next week, but would appreciate it if anyone has any insight or has experienced a similar upshifting problems.

Thank you in advance. My apologies if this topic has been covered in a past thread.

Best,

Can

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Thank you everyone for response on my concern topics, I have tried shifting as tta300 suggested, but it didn't work on mine! I guess I should try Brian suggestion on "speed sensor", but i'm not sure this is going to work because the guy he rebuilt my tramission said "speed sensor" has nothing to do with it. They did a scan test and they said my Knock sensor is bad, it might be the reason too! I'm so confused, It cost me alot of money to rebuit my transmission and now every thing seems never fixed and they kept sugesting to changing things that they are really not sure and me neither! Please help!

thanks a billion!

Phong

I had hard shifting and loss of overdrive gear on my 99RX with 175,000 miles on it and everyone was telling me it's time to rebuild the transmission for $5,000. I took it to some small transmission shop and the old guy there replaced a "speed sensor" and it works fine, better than ever. I also had him flush the transmission and replace the fluid, but the sensor was the real fix. I'm sure it could use rebuilding after this many miles, but I was thrilled to get by for $200 and still use it as a spare vehicle in the winter and other times.

Good luck,

Brian

Hello Can,

I have the exact same problem, I wonder what it was in your case! How did you fix it. I took to the repair shop they said it tranmission and need to replace and after they rebuilt the problem seems never fixed. Please let me know or email me at nguocphong@gmail.com. It cost me too much money but the problem never fixed!

thank you,

nguoc phong

Hello,

I'm a first time poster to the forum. I have a 99 RX300, fwd, 128K.

I have just recently experience a problem of not being able to shift from 3rd to 4th gear. After getting to 40 mph, it appears that there's no up shifting for any speed higher. The RPM at 60 mph is around 3K, and 70 mph is around 4K.

I checked my fluids (oil and transmission) and they appear to be in line. I don't know if this is the beginning signs of a transmission overhaul. I'm planning to take it to nearby shop next week, but would appreciate it if anyone has any insight or has experienced a similar upshifting problems.

Thank you in advance. My apologies if this topic has been covered in a past thread.

Best,

Can

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Assuming no CEL or other diagnostic indication your engine may have simply degraded to the point wherein 4th(OD) can no longer be supported.

As a test I would disconnect the battery for about 10 minutes to reset the system's "learned" parameters. If the OD then works for a short period or time then "learns" not to use OD again then you likely need an engine overhaul.

You might also try a FULL tank of premium fuel to help bring the engine back into the required OD RPM/torque range

What am I missing here? The OP writes about his trans not going into overdrive, and you are talking about premium fuel and engine overhaul. Call me lost and confused. Can you elaborate and tell me how someone, who writes about transmission problems needs to have his engine rebuilt? I didn't read a single complaint about engine, engine parameters, inability to accelerate, rough running or such.

It is my understanding that, once a certain engine rpm and temperature have been reached, then the trans shifts into OD.

Gary

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"..knock sensor is bad..."

That could mean it "triggers" too quickly or it could mean it never triggers at all.

In either case a knock sensor failure code would undoubtedly cause the engine/transaxle ECU to NEVER shift into OD.

The OD gear ratio is designed to operate the engine at the optimum RPM for conserving fuel. Therefore it would not be at all unusual at specific road speeds for the engine to be operating right on the "cusp" of being in the range of lugging, or knocking due to lugging the engine. The firmware is designed to QUICKLY downshift out of OD the instant engine knock due to lugging is detected. So it would make sense that a failing, failed knock sensor would result in non-use of OD.

Obviously a "tired", worn out engine would be much more likely to knock due to lugging at a higher RPM than a brand new engine thus the question of mileage.

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