The 4L60E uses two on/off shift solenoids, called A (the 1-2 solenoid) and B (the 2-3 solenoid), to select its four forward gears. It also has a pressure control solenoid that sets line pressure, a torque converter clutch solenoid (and on many later units a PWM converter clutch solenoid), and a 3-2 downshift control solenoid. All of them bolt to the valve body inside the transmission, under the oil pan.
4L60E shift solenoid chart
| Gear | Shift solenoid A (1-2) | Shift solenoid B (2-3) |
|---|---|---|
| 1st | On | On |
| 2nd | Off | On |
| 3rd | Off | Off |
| 4th | On | Off |
Because both solenoids are off in third gear, a 4L60E that loses electrical control defaults to third gear in drive, which is why limp mode often means starting from a stop in third; see limp mode.
4L60E solenoids and what they do
- Shift solenoid A (1-2): controls the 1-2 and 3-4 shifts. A failure can make the transmission start in second or skip gears.
- Shift solenoid B (2-3): controls the 2-3 shift. A failure can leave it stuck in a low gear or starting in a higher one.
- Pressure control solenoid: sets line pressure; a fault causes harsh or soft shifts and can lead to clutch damage.
- Torque converter clutch solenoids: lock and unlock the converter; faults cause no lockup or shudder (P0740, P0741).
- 3-2 control solenoid: smooths the 3-2 downshift.
Bad 4L60E shift solenoid symptoms
- Stuck in one gear, or starting from a stop in second or third
- Missing a gear, or delayed and harsh shifts
- Check engine light with codes such as P0753, P0750 or P0700
- Symptoms that come and go as the transmission warms up
See transmission solenoid symptoms for the general picture.
Where are the 4L60E shift solenoids?
Remove the transmission oil pan and filter, and the solenoids are visible on the valve body. Shift solenoids A and B sit in bores on the valve body, held by retaining clips, and connect to the internal wiring harness that runs to the case connector on the side of the transmission. The pressure control solenoid and converter clutch solenoids are also on the valve body.
How to test and replace them
- Read codes with a scan tool that reads the transmission side of the engine computer.
- Check resistance at the case connector against the specification; this tests the solenoids and the internal harness together.
- Command the solenoids with a bidirectional scan tool and listen for clicks or watch gear changes.
- To replace, drain the fluid, drop the pan and filter, remove the retaining clip and pull the solenoid; install the new one with new O-rings, then refill with Dexron VI to the correct level.
When it is more than a solenoid
If new solenoids do not cure slipping or missing gears, or the pan has heavy friction material and metal, the problem is internal; see 4L60E rebuild or replace, 4L60E problems and our 4L60E transmissions.
Trouble codes: P0751 Shift Solenoid A Stuck Off · P0756 Shift Solenoid B Stuck Off · P0758 Shift Solenoid B Electrical · P0748 Pressure Control Solenoid A Electrical · all OBD2 codes.
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