6T30 Shift Kit 2013-17

The 6T30 sits behind the smaller engines in GM's compact cars, such as the Chevrolet Cruze and Sonic, and most owners shopping for this kit describe the same thing: shifts that feel slurred instead of crisp, a converter clutch that seems to engage and release on its own at steady speed, or a check engine light with pressure control or gear ratio codes that a fluid change did not clear. This listing is the new TransGo SK 6T40-G2 SHIFT KIT valve body repair kit for 2013-2017 Gen 2 units. It is a repair kit for the valve body you already have, not a replacement valve body.

What the shift kit does in a 6T30

The 6T30 shares its hydraulic, mechanical and electrical design with the 6T40, 6T45 and 6T50; the main differences are lower torque capacity and a smaller case. That shared design is why one TransGo kit serves the whole Gen 2 family. Inside the valve body, the actuator feed limit (AFL) valve is spring calibrated to keep solenoid feed pressure from rising past a set limit regardless of line pressure. If that feed is too high or too low, every solenoid's output is off by the same amount, and the TCM sees ratio and performance faults. The pressure regulator valve's spring end carries the EPC boost signal, and wear there gives lazy boost and low line pressure. The TCC regulator valve bore wears too, which is what produces converter clutch slip codes. This kit replaces all three with hardened steel valves made in the USA: an oversized AFL valve, a drop-in pressure regulator valve and spring with longer lands, and a drop-in TCC regulator valve with a scarf cut seal, spring and sizing O-ring.

Symptoms on a 6T30

• Soft or flaring upshifts, often most noticeable on the 1-2 and 2-3
• TCC hunting or slip at a steady cruise, with P0741
• Clutches that burned up, sometimes soon after a rebuild
• Slow pressure rise when you accelerate hard
• Codes on TransGo's list for the kit: P0751, P0752, P0776, P0777, P0796, P0797, P2714, P2715, P2723 and P2724

How to confirm it before you buy

Rule out the easy causes first. Check the fluid level hot at the check plug and look at the fluid and pan debris. Then look at the TCM's adaptive learning: ATRA's GEARS Magazine notes that frozen adapts, or adapts reset by power loss, voltage swings or bad grounds, cause shift complaints and codes on this family before anything is worn out. Test battery, grounds and charging, and run a fast learn on a healthy car before condemning the valve body. Solenoid faults read much the same as worn bores, so work through the resistance checks in our 6T40 family shift solenoid guide. If the car will not reach 5th or 6th, read 6T40 won't shift into overdrive first.

Fitment

TransGo lists the SK 6T40-G2 for 2013-2017 Gen 2 6T30, 6T40 and 6T45 transmissions without pressure switches. A 6T30 with pressure switches on its control solenoid body is Gen 1 and needs the 6T30 shift kit for 2007-2012. TransGo also notes the family moved to Gen 3 at the start of 2015 model year production, adding an off-axis, chain-driven pump; on the 6T30 side that unit is the 6T31 and takes the separate SK 6T40-G3 kit. On a 2015-2017 car, look at the pump drive before ordering. When in doubt, send us your year and VIN. The identical kit is also listed as the 6T30 shift kit 2013.

Install notes

• Budget for TransGo's AFL-G2-TK tool kit, a high-speed steel reamer and three guides, sold separately. The oversized AFL valve depends on it, and the kit's instructions mark which bore to ream.
• The two drop-in valves need no machining; the scarf cut ring on the TCC regulator valve seals in the original worn bore.
• Leave each solenoid in its factory position on the TEHCM and replace a weak one now; a 6T30 TCC solenoid is worth fitting if converter clutch codes were part of the complaint.
• If the unit is apart for burned clutches, inspect the drums for scoring and wear; we stock a 6T30 clutch drum listed for 2013 if yours is damaged.
• Refill with Dexron VI. Before the Service Fast Learn, the listed conditions include wheels blocked, brakes applied, closed throttle, fluid at 158-239 F, and the selector cycled from Park to Reverse three times to purge air.

Why is a 6T30 kit called SK 6T40-G2?

The 6T30, 6T40, 6T45 and 6T50 share the same valve body design, so TransGo makes one Gen 2 kit for all of them and names it after the 6T40.

Does my 2014 Cruze have a Gen 2 transmission?

Check for pressure switches on the control solenoid body. If there are none and the pump is not the later chain-driven type, this kit fits; if there are switches, you need the Gen 1 kit. Your VIN settles it.

Is the reamer included?

No. The oversized AFL valve requires TransGo's AFL-G2-TK tool kit, which is sold separately.

Can a dead battery cause shift problems that look like this?

Yes. Adaptive values can reset or freeze after power loss, voltage problems or bad grounds. Fix the electrical side and run a fast learn before buying parts.

What do I do after installing it?

Refill with Dexron VI, set the level hot at the check plug, and run the Service Fast Learn with the fluid between 158 and 239 F.

• 6T40 Shift Solenoid Symptoms and Replacement
• 6T40 Won't Shift Into Overdrive: Causes and Fix
• 6T40 Valve Body Symptoms: What Wears, What It Does to the Drive, and How to Test It
• 6T40 Fluid Change Cost