4L70E Solenoid Kit 2009, new and ready to install. Fits the 4L70E. Ships fast from the USA.
If your 2009 Silverado, Sierra, Tahoe or Yukon with the 4L70E is slamming into gear, flashing a solenoid code, or dropping into a third-gear limp mode every time it gets hot, the electrical side of the valve body is the first place to look. This is a new 4L70E solenoid kit listed for the 2009 model year. The product photo shows a complete internal wiring harness together with the solenoid set: the two on/off shift solenoids, the pressure control (EPC) solenoid, and the small spool-type solenoids that handle the 3-2 downshift and converter clutch apply. Replacing the harness and every solenoid at once removes the guesswork of finding one tired coil at a time on a truck that has a decade or more of heat cycles behind it.
By 2009 the 4L70E had been in production for three model years. ATRA's pre-release GM update describes it as a new model introduced for 2006 using the same electronic technology as the updated 4L60E and 4L65E, which is why so many parts cross between them. The transmission computer never moves a shift valve by itself. It switches the A and B shift solenoids on and off in a fixed pattern (ATRA's chart lists first as on/on, second off/on, third off/off and fourth on/off), and line pressure moves the valves. The EPC solenoid works the other way around from what most people expect: more current means less pressure. ATRA's Gears magazine puts the command at roughly 0.9 to 1.1 amps at idle, falling toward zero at wide open throttle when the transmission needs maximum pressure. A weak EPC coil therefore shows up as soft, slipping shifts or as harsh, high-pressure engagement depending on how it fails.
Pull codes first and note which ones return after clearing. On the EPC circuit, an amp clamp is better than an ohm reading: a commanded current that matches the scan tool but no change in pressure points to the valve body, not the solenoid. Our 4L70E EPC solenoid symptoms guide walks through that test. Be careful with P1870 and P0894. Sonnax ties those codes to wear in the isolator bore, where the TCC regulator valve sits, and new solenoids will not cure a worn bore. If the codes look hydraulic, read 4L70E valve body problems and testing before ordering.
Listed for the 2009 4L70E. GM's own owner literature for the Tahoe calls this unit the 4L70-E Super Duty transmission, and it was used in the half-ton GM trucks and SUVs of the era plus some Cadillac and Pontiac models. Because the 4L60E, 4L65E and 4L70E share a case design, the tag alone can mislead you. Compare the case connector, the harness routing and the solenoid connectors in the photo with the parts on your valve body, or send us your year and VIN before ordering. Every other part for this unit is on the 4L70E collection page.
Drain the pan, drop the filter and photograph the harness routing before you unplug anything. Remove the solenoids one at a time and keep the retaining clips and bolts in order. Inspect the case connector for spread or corroded pins. Lube each new O-ring with ATF so it does not roll when the solenoid seats, route the new harness exactly like the old one, and keep it clear of moving parts. Refill with DEXRON-VI, which GM specifies for this transmission, then clear codes and road test through every gear so the computer can adapt shift timing. If the valve body bores are worn, pair the job with the 2006-2013 4L70E valve body. If you only need the converter clutch side, the 4L70E TCC solenoid is sold separately, and a replacement 4L70E internal wiring harness is available on its own if your solenoids test good.
| Fits | 4L70E 2009 |
| Part type | Solenoid Kit |
| Condition | New |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
The product photo shows a complete internal harness with the solenoids. Compare the harness and connectors in the photo against your own valve body before installing.
It is listed for 2009. Nearby years often share solenoids, but connectors and harness layouts changed during the 4L60E-family updates, so send your year and VIN and we will confirm.
Possibly. Third is the default gear when both shift solenoids are off, so a blown fuse, a bad harness or a failed power feed can cause it too. Check power at the case connector first.
Not if the cause is hydraulic. Sonnax links those slip codes to isolator bore wear in the valve body. Test before assuming the solenoids are at fault.
DEXRON-VI automatic transmission fluid, which GM specifies for the 4L70E. Fit a new filter and pan gasket while the pan is off.
