700R4 Solenoid Kit, new and ready to install. Fits the 700R4. Ships fast from the USA.
This listing is the TCI 376600 universal lockup wiring kit, the parts a 700R4 needs to lock its torque converter when there is no factory computer behind it. If you dropped a 700R4 into a C10, a Nova, a Camaro or any carbureted hot rod and the engine still sits a few hundred rpm high in overdrive on the highway, the transmission is usually fine. Nothing is switching the converter clutch on. TCI also lists it for 200-4R installs and for pre-1993 GM vehicles where the original engine computer has been removed.
Every factory 700R4 has a converter clutch circuit controlled by a solenoid inside the case. In the original truck or car, the computer grounded that solenoid once the vehicle was warm, at speed and in a high gear. Pull the computer out, or install the transmission behind an engine that never had one, and the solenoid never gets a signal. The converter then slips all the time, which shows up as extra rpm, extra fluid heat and lost mileage.
The TCI kit replaces that computer decision with two switches. A 4th gear pressure switch, mounted inside the transmission, only closes when the unit is actually in overdrive. An adjustable vacuum switch under the hood reads engine vacuum, so the converter stays locked at a steady cruise and releases as soon as you get into the throttle or the transmission downshifts. TCI says the vacuum point can be set to different levels, and there is a manual override if you want to switch lockup on or off yourself.
It will not cure a converter that shudders when it applies, a transmission that never reaches 4th, or a burned 3-4 clutch. Those are hydraulic or internal problems, and our 700R4 common problems guide covers how they show up.
Drive the vehicle warm and watch the tachometer. The transmission should shift into 4th by itself. If it does and the rpm never drops a second time a few seconds later, the converter is not locking, and on a non-computer install this kit is the missing piece. If it never upshifts to 4th, fix that first, because the 4th gear switch will never close. Check the TV cable adjustment as well; our 700R4 TV cable guide explains why a slack cable causes late, soft shifts and 3-4 clutch damage. Finally, confirm the converter in the car is a lockup converter. Some aftermarket stall converters are non-lockup and nothing in the wiring will change that.
Fits the GM 700R4 (4L60) and the 200-4R in non-computer applications. This is TCI part number 376600. The pan gasket in the box is the 700R4 pattern only, so a 200-4R owner needs to buy a 200-4R pan gasket separately. Our 200-4R vs 700R4 guide shows how to tell the two apart. If the vehicle still runs its factory computer, the lockup is already controlled and you do not need this kit. Browse every part for this unit on our 700R4 parts page, or send us your year and VIN before ordering if you are unsure what is in the car.
Since the pan is already off, it is a good time to fit a 700R4 shift kit, and a fresh TV detent cable makes sure line pressure is right before you start locking the converter on the highway.
| Fits | 700R4 |
| Part type | Solenoid Kit |
| Condition | New |
| Brand | OEM |
| Reference | 376600 |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
No. TCI lists the contents as the pan gasket, wiring harness, vacuum switch, 4th gear pressure switch, splice connectors and mounting screw. It powers the converter clutch solenoid already in the 700R4.
Yes, TCI lists it for both the 700R4 and 200-4R. The included pan gasket only fits the 700R4, so buy a 200-4R pan gasket separately.
No. A factory computer already controls converter lockup. This kit is for swaps and for pre-1993 vehicles where the computer has been removed.
Yes. Lockup is automatic through the vacuum switch, and TCI includes a manual override option so you can force it on or off if you want.
Check that the transmission reaches 4th, that the converter is a lockup type, and that the vacuum switch is on full manifold vacuum and adjusted for your engine. A worn converter clutch or valve body can also prevent lockup.
Refill with Dexron ATF and set the level with the transmission at operating temperature.
