Transgo SK 6T40-A valve body repair kit for Gen1 6T30, 6T40 and 6T45 units, fixing worn AFL, TCC regulator and line pressure bores without reaming.
If your 2007-2012 GM 6T30, 6T40 or 6T45 has a torque converter clutch that hunts or shudders, soft or flaring 1-2 and 2-3 shifts, burned friction plates from low apply pressure, or a pile of pressure-switch codes that keeps coming back, the valve body bores wearing egg-shaped are usually why. The Transgo SK 6T40-A is a repair kit, not a replacement valve body - it drops new valve trains into the bores you already have instead of reaming them oversize, so you fix the worn casting rather than paying for a whole new one.
The valve body is the hydraulic brain of the 6T30/6T40/6T45, routing line pressure through precision bores to apply each clutch and band while the solenoids bolted to it time every shift. On a Gen 1 casting, three circuits wear the fastest: the AFL (actuator feed limit) valve that sets solenoid feed pressure, the TCC regulator valve that controls torque converter clutch apply, and the pressure regulator valve that sets line pressure and boost response. Transgo's kit rebuilds all three with hardened, longer-land valves and a complete drop-in AFL assembly sized to seal in a worn bore, rather than asking you to source an oversize reamer and a donor casting.
Scan for codes and match them against the list above, then check whether the complaint is pressure-related rather than a mechanical clutch or band failure - this kit restores hydraulic control, it does not replace worn frictions or a cracked drum. Our 6T40/6T45 valve body symptoms and testing guide covers how to isolate a bore-wear complaint from a solenoid-only fault, and 6T40 common problems and fixes details the pressure-switch and wave plate issues that often show up at the same time.
This is a Gen 1 kit only, covering the 2007-2012 GM 6T30, 6T40 and 6T45 as used in the 2008-2012 Chevrolet Malibu and Equinox, 2011-2012 Cruze, Buick LaCrosse and Regal, GMC Terrain and Saturn Vue. Confirm your build before ordering: the Gen 2 valve body introduced for 2012-2017 uses a different casting entirely and takes a different kit, so check your RPO code if your Cruze, Equinox or Terrain falls near the changeover year. The full Gen 2 valve body casting is the part you need instead.
No reaming is required - the kit's valves are sized to seal in your existing bores, so the job is a drop-in rebuild rather than a machining job. Replace the TEHCM pressure switch diaphragms with the new O-rings included while the valve body is apart, change the filter and fluid with Dexron VI at the same time so debris already in the pan does not circulate through the freshly rebuilt circuits, and torque the valve body bolts to spec in sequence. A valve body locating tool keeps the casting centered while you snug the bolts down. Clear codes and run the TCM's adaptive relearn afterward, and if your original unit had enough mileage to burn frictions, pair this repair with a 6T40E/6T45E master rebuild kit rather than running new valving against worn clutches.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is a repair kit. The Transgo SK 6T40-A drops new, properly sized valve trains into your existing bores instead of reaming them oversize, so you repair the worn casting you already have rather than buying a whole new one.
No - this is a Gen 1 kit for 2007-2012 units only. The Gen 2 valve body introduced for 2012-2017 uses a different casting and needs a different kit. Check your RPO code if your vehicle is near the changeover year.
Pressure-switch and pressure-control codes including P0741, P0751, P0752, P0757, P0776, P0777, P0796, P0797, P0842, P0843, P0872, P0873, P0877, P0878, P0989, P0990, P2714, P2715, P2723 and P2724.
No - the kit's valves are sized to seal in the bores as they already are after wear, which is the point of the kit versus a reaming repair.
New O-rings and diaphragms to renew the TEHCM pressure switches while the valve body is apart.
This kit restores hydraulic pressure control - it will not repair worn frictions or a damaged drum. If your unit has real mileage and burned clutches, pair it with a 6T40E/6T45E master rebuild kit.
