Controls the torque converter lockup on a GM TH700R4 or 4L60 behind a carbureted or non-computer engine, so 4th gear locks the converter with no aftermarket ECU.
You swapped a TH700R4 behind a carbureted small block, a hot rod, a C10 or a classic Camaro, and now the overdrive works but the tachometer never drops that last few hundred rpm on the highway. The transmission is not broken. In the factory vehicle a computer told the converter clutch when to apply, and in your swap nothing is sending that signal. The Painless 60109 kit gives the transmission that signal with no computer at all, on carbureted or fuel injected engines.
A torque converter always slips a little because it couples the engine to the transmission through fluid. Inside a lockup converter is a clutch that, when applied, mechanically ties the converter cover to the turbine so the engine and input shaft turn together. In a 700R4 that clutch is applied by a solenoid on the pump side of the case: when the solenoid is powered it closes an exhaust, oil pressure moves the converter clutch apply valve, and the converter locks. With no power to the solenoid, the converter never locks, slip turns into heat, and the fluid runs hotter all day on the highway. Our 700R4 TCC lockup guide walks through the hydraulic side in more detail.
Painless wires the solenoid through three switches in series, so all three conditions must be true before the converter applies:
The kit includes the vacuum switch, the 4th gear pressure switch, the brake switch, the lockup solenoid, an 11 ft color coded harness, a new pan gasket and mounting hardware. You supply a 20 amp fused power source; no fuse is included.
Make sure the transmission upshifts into 4th on its own and holds it. If it never reaches overdrive, read our 700R4 won't shift into overdrive guide first, because lockup can only happen in 4th with this kit. Next, check that your converter is actually a lockup converter; some aftermarket stall converters are not, and the kit cannot lock a converter that has no clutch inside.
This kit fits the GM TH700R4 with the early square Weatherpack case connector, which covers the 1981-1990 units. GM renamed the transmission 4L60 in 1990, and the 1990-1993 units moved to a round 5-pin connector, so look at your case connector before ordering. It works on carbureted and fuel injected engines. It is not for the electronic 4L60E, which needs a computer to shift. Browse the rest of our 700R4 parts, or send us your year and transmission ID if you are not sure which case you have.
Minor transmission disassembly is required. Drain the fluid, drop the pan and filter, mount the solenoid and the 4th gear pressure switch, then route the harness out through the case connector. Under the hood, mount the vacuum switch on a manifold vacuum source and wire the brake switch, then feed the circuit from a 20 amp fused source. Refill with fresh ATF and confirm that the rpm drops at steady cruise in 4th and releases on throttle and brake. Since the pan is already off, it is a good time to add a transmission cooler; if the unit has unknown history, a 700R4 rebuild kit is the next step.
| Fits | GM TH700R4 / 4L60, 1981-1990 (early square Weatherpack connector) |
| Engines | Carbureted or fuel injected, no factory transmission computer required |
| Includes | Vacuum switch, 4th gear pressure switch, brake switch, TCC lockup solenoid, wire harness, pan gasket, mounting hardware |
| Function | Locks the converter clutch only in 4th gear; releases under load and on braking |
| Solves | No highway lockup on a swapped 700R4: converter slip, high fluid temp, lost overdrive MPG |
| Part reference | Painless / Edelbrock 60109 |
| Ships | From the USA |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Probably not. This kit uses the early square Weatherpack connector found on 1981-1990 TH700R4 cases. The 1990-1993 units renamed 4L60 use a round 5-pin connector. Check your case connector before ordering.
No. The vacuum switch, 4th gear pressure switch and brake switch control the lockup solenoid on their own. You only need a 20 amp fused 12 volt source, which is not included.
That is by design. The vacuum switch opens when manifold vacuum drops under load, so the converter unlocks for passing and hills, then locks again at steady cruise.
Yes. Painless lists the 60109 for both carbureted and fuel injected engines, which is the main reason people buy it for 700R4 swaps.
Yes. The solenoid and 4th gear pressure switch mount inside the transmission, so you drain the fluid and remove the pan and filter. A new pan gasket is included in the kit.
