Shifting the transmission into Drive or Reverse results in a whirring noise and the car is slow to shift into gear?

Tiny
TSTOCKWELL1936
  • MEMBER
  • 2007 LEXUS IS 250
  • 2.5L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 189,000 MILES
My vehicle listed above starts and runs fine in park and neutral. No stalling.

Shifting into Drive or Reverse results in a whirring noise and the car is slow to shift into gear. When shifting into drive, the car will go very slow, and trying to accelerate past 20 or so MPH creates the whirring noise again.

I drove it for half a mile at 20mph to get it home.

Possible issue; Torque converter or Differential?

Looking for a diagnosis and the possibilities. Thank you.
Thursday, March 14th, 2024 AT 11:57 AM

7 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,716 POSTS
Hi,

If the differential was faulty, it could make the noise, but the slow acceleration is unlikely. When you try to accelerate, does the engine speed up but the car doesn't? Have you checked to make sure the fluid is both clean and full?

https://www.2carpros.com/articles/how-to-check-and-add-transmission-fluid

Also, yes, it could be related to a line pressure issue or the torque converter. We should try scanning the can-bus to see if there are related diagnostic trouble codes present.

Here is a link showing how it's done:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Let me know.

Joe
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Thursday, March 14th, 2024 AT 8:14 PM
Tiny
TSTOCKWELL1936
  • MEMBER
  • 5 POSTS
The transmission is a closed system, and I am not able to access it from underneath the car myself, with a bad back.

Yes, when I try to accelerate, the engine speeds up but the car doesn't. In fact, although I drove it 1/2-mile home, it is not drivable now. Any acceleration above even 5 to 10 MPH causes the car to stop as if it is in neutral. Feathering the gas allows minimal reverse or drive.
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Friday, March 15th, 2024 AT 2:36 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,716 POSTS
Hi,

Either the clutches in the transmission are worn allowing them to slip, the fluid is low, or there could be a line pressure issue.

Since the vehicle is too low to check the fluid (I completely understand, especially with a bad back) the next thing to do is have the CAN-bus scanned to determine if there are related codes. If this is the original transmission, it could have simply failed due to wear.

Here is the link again for scanning. If possible, see if you can get your hands on a scan tool that can read codes from the can-bus.

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Let me know if this is something you can do or have done.

Take care,

Joe
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Friday, March 15th, 2024 AT 7:09 PM
Tiny
TSTOCKWELL1936
  • MEMBER
  • 5 POSTS
The trouble code of DTC 1201 came up. This may indicate a faulty ECM?
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Sunday, March 17th, 2024 AT 1:51 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,716 POSTS
Hi,

Is that a C1201? If it is, that is related to the vehicle stability system. That could be directly related to the transmission if it is slipping.

Let me know if it is a C code. Also, if that is the only code present. It may be related to the ECM if it is an output code. Actually, 99% of the time that is the problem.

Let me know. Also, let me know if the code has the number 51 after it (C1201-51)

Take care,

Joe
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Sunday, March 17th, 2024 AT 8:08 PM
Tiny
TSTOCKWELL1936
  • MEMBER
  • 5 POSTS
Yes, it is a C Code (sorry left the C out). C1201.

No other codes.
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Sunday, March 17th, 2024 AT 8:39 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,716 POSTS
Hi,

We need to have a bi-directional scan tool to determine if that is an output code or not. If it is, my first suspect is the ECM. Is that something you can have done?

Joe
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Sunday, March 17th, 2024 AT 9:20 PM

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