Transmission is slow in shifting from 2nd to 3rd?

1996 GMC C2500

270,000 MILES • V8 • 2WD • AUTOMATIC

RLBSTOCKTON

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Instructions for replacing 2-3 shift solenoid. OBDII code P0756 (4L80-E) Transmission is slow in shifting from 2nd to 3rd. Occasional MIL lights up and wont't shift to 3rd. Turn ignition off, restart and will then shift. Have changed fluid and filter.

Transmission was replaced with rebuilt at 145000 miles. Now have 270000 miles on vehicle.

Jul 25, 2011 at 12:27 AM

SQM

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Hello,

I have attached the shift solenoid replacement procedure below.
This will require you to remove the valve body and access the shift solenoids.

https://www.2carpros.com/articles/automatic-transmission-problems

Please let me know if you have any questions.
Thank you.

Images (Click to enlarge)

Dec 16, 2021 at 8:22 PM