Five solenoids plus a new pressure switch manifold for 2003-up GM 4L60E and 4L65E: shift A and B, 3-2, EPC and TCC/PWM in one kit.
A 2003-or-later 4L60E or 4L65E that starts out in second or third, flares between gears, shudders on lockup, or keeps returning with a cluster of codes such as P0751, P0756, P0748, P0742 and a pressure switch code like P1810 often has two problems at once: tired solenoids and a leaking pressure switch manifold. This six-piece kit replaces both in one pan drop. You get the A and B shift solenoids, the 3-2 downshift solenoid, the EPC pressure control solenoid, the TCC/PWM lockup solenoid and a new manifold pressure switch.
Every hydraulic decision in a 4L60E starts with an electrical signal. The PCM switches the A and B solenoids in a fixed pattern to pick the gear (ATRA lists first as ON/ON, second OFF/ON, third OFF/OFF and fourth ON/OFF), varies the EPC solenoid to set line pressure, pulses the TCC/PWM solenoid to apply the converter clutch, and fires the 3-2 solenoid to time kickdowns. All of them work off AFL oil that the AFL valve regulates to about 115 psi, according to Sonnax.
The pressure switch manifold, also called the TFP switch, is the PCM's feedback. It sits on the valve body and reports which range the manual valve is in, from park to manual low. If one of its internal diaphragms leaks, the PCM can read the wrong range. It may then command the wrong shift pattern or line pressure, or set a TFP code with no other fault present. That is why it belongs in the same job as the solenoids rather than as an afterthought.
Start with the scan tool. Watch the TFP range parameter while you move the shifter through every position with the engine idling; if the reading lags, skips or shows a range you did not select, the manifold is suspect. Then check solenoid resistance at the case connector against ATRA's bulletin values: 20 to 40 ohms for the shift solenoids and 3.5 to 8.0 ohms for pressure control. ATRA also traced several solenoid codes on one 4L60E to a single bad terminal crimp, so inspect the pins before blaming parts. If the electrical side tests clean but the shift complaint stays, the valve body bores may be worn, and the Sonnax vacuum test procedure will show it. Our 4L60E shift solenoid testing guide and P0748 pressure control guide go through each step.
This kit is listed for the GM 4L60E and 4L65E from 2003 and up, which covers the later full-size Silverado, Sierra, Tahoe, Yukon, Suburban and related GM trucks and SUVs. The 2003-up transmissions use a different pressure switch manifold and EPC connector than the 1993-2002 units, so a 2002 or earlier truck needs a different kit. Compare the manifold and connector shapes to your old parts, or send us your year and VIN to check. Browse the rest of the range on our 4L60E parts page.
Drain and drop the pan, remove the filter, and unplug the internal harness from each solenoid and the pressure switch. Work one component at a time so nothing ends up in the wrong bore. The pressure switch manifold bolts to the valve body; clean the mating surface and tighten its bolts evenly to factory spec so it seals all the way around. Lube every new O-ring with ATF before seating a solenoid. With the pan off, look at the internal harness insulation and connector pins, because this kit does not replace the harness.
Refill with Dexron VI, clear codes, perform a shift relearn, and road test through every gear and a lockup cycle. Fit a new filter and pan gasket at the same time; our 4L60E solenoid and filter service kit covers it. If the vacuum test shows bore wear, a replacement 4L60E valve body is the lasting fix.
| Includes | A shift, B shift, 3-2 downshift, EPC, TCC/PWM solenoids, manifold pressure switch |
| Pieces | 6 |
| Fits | GM 4L60E, 4L65E 2003-up |
| Weight | 1.65 lb |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is the manifold pressure switch, often called the TFP switch. It bolts to the valve body and tells the PCM which gear range is selected. When it leaks, the PCM can set range or shift codes even if the solenoids are good.
No. It is for 2003 and newer 4L60E and 4L65E units. The 1993-2002 transmissions use a different pressure switch manifold and EPC connector.
No. The kit has five solenoids plus the pressure switch. Check the old harness for heat-cracked insulation or loose terminals while the pan is down, and replace it separately if needed.
A faulty range signal can make the PCM pick the wrong strategy, and electrical faults in the shift circuit can force a fail-safe gear. Check the TFP range reading on a scan tool alongside the solenoid codes before replacing parts.
Refill with Dexron VI, clear codes, and run a shift adapt relearn with a scan tool so the PCM resets its learned shift pressures.
