4L70E Shift Kit, new and ready to install. Fits the 4L70E. Ships fast from the USA.
A 2006-2013 Silverado, Sierra, Tahoe, Yukon or Trailblazer SS that sets P1870, shudders at 45 mph, or slams into second after a cold start is showing the classic signs of a worn 4L70E valve body. This listing is the TransGo SK4L60E shift kit, the same part number for the 4L60E, 4L65E and 4L70E, and it is built around fixing exactly those complaints. It is new, US-made, and includes the parts for trucks with and without cylinder deactivation.
Most 4L70E drivability problems start in one small bore. The converter clutch isolator and regulator valves slide back and forth thousands of times as the computer modulates lockup, and the aluminum bore wears oval. Oil leaks past the worn lands, the converter clutch slips, and the computer logs P1870 or P0894. Then it tries to protect the converter by raising line pressure, so the 1-2 shift turns harsh. Sonnax describes the same oscillation-driven wear in its isolator bore article.
TransGo's answer is a drop-in hardened steel valve with longer lands that ride on unworn sections of the bore, so the circuit seals again without reaming. The rest of the kit recalibrates the shift timing: new 1-2 and 3-4 accumulator springs, second servo springs and a coil spacer, pressure regulator springs, a stronger actuator feed limit spring, and a wire spacer that keeps the EPC screen from collapsing at heavy throttle and starving the transmission of line pressure. Together these shorten every apply so the 2-4 band and 3-4 clutch stop slipping themselves to death.
Read the codes and freeze frame first. A TCC slip code with no solenoid circuit codes points to the hydraulic side this kit repairs. If the code is P0741 with a TCC solenoid circuit fault, or the pressure control solenoid is out of range, test those electrically before buying hydraulics; our EPC solenoid guide walks through reading the amps. TransGo also gives a simple lockup check once the kit is in: drop the pan, place a 5/16 or 3/8 inch ball in the TCC solenoid snout, reinstall, and put it in gear. If the engine does not chug or stall, the converter or its seals are leaking and the transmission has to come out. Our 4L70E common problems guide covers the other failures that mimic a worn valve body.
The listing covers the 4L60E, 4L65E, 4L70E and 4L75E. TransGo rates the kit for 1993-2015 4L60E, 4L65E and 4L70E, except hybrids. The important split on later trucks is cylinder deactivation (Active Fuel Management). On AFM trucks, the computer slips the converter on purpose when cylinders shut off, so TransGo has you install the supplied spacer instead of the blue spring behind the new converter valve, and use a converter with woven carbon lining. Non-AFM trucks use the blue spring. Most 2009 and later units also dropped the 3-2 solenoid, and the instructions skip that step for them. Separator plates also changed in 2007 and 2009, so match plate replacements to your year. Send us the year and VIN if you are not sure which you have, and see the full 4L70E parts collection.
The kit is written for experienced transmission technicians. Valve body, servo and accumulator steps can be done with the transmission in the vehicle, but the bolt pattern matters: TransGo warns that a wrong-length valve body bolt can lock the gear train. Pick the 1-2 accumulator spring from the chart using your second servo piston number and accumulator bushing code, and verify band clearance. Refill with Dexron VI, and check the level hot on the dipstick; GM's owner manual lists 5.0 quarts as the 4L70-E service fill. Replace a sticking or out-of-spec TCC solenoid at the same time, and if the 3-4 clutch is already burnt, install the kit as part of a master rebuild kit overhaul.
| Fits | 4L70E |
| Part type | Shift Kit |
| Condition | New |
| Brand | TransGo |
| Ships | From the USA |
| Warranty | 1-year |
Yes. TransGo uses SK4L60E for the whole family and lists it for 1993-2015 4L60E, 4L65E and 4L70E transmissions, except hybrids.
Those codes are TransGo's headline complaints for this kit. The new converter isolator and regulator valve seals a worn bore, which is the usual cause. Clear the code after install and road test; if it returns, check the converter and TCC solenoid.
No, but it changes one step. AFM trucks use the supplied spacer behind the converter valve instead of the blue spring, and should run a converter with woven carbon lining. The instructions list which trucks have cylinder deactivation.
Not for the valve body, servo and accumulator work. The pump and reverse input piston steps are done when the unit is apart, so many shops install the full kit during a rebuild.
Dexron VI. The GM owner manual lists 5.0 quarts as the 4L70-E service fill; check the level hot on the dipstick after the road test.
