6T30 Pressure Control Solenoid

The 6T30 is the lightest-duty member of the GM 6T30/6T40/6T45/6T50 six-speed family, the version paired with small four-cylinder engines in compact Chevrolet and Buick models. When one of these cars starts flaring between gears, slamming into Reverse, or storing a pressure control solenoid code, a lot of owners are quoted a full control module. This part is a cheaper first step: a remanufactured solenoid body carrying all seven solenoids, as pictured, ready to swap as one piece.

What the pressure control solenoids do in a 6T30

Shifts in this family are clutch-to-clutch, so the transmission computer has to release one clutch while applying the next, and it does that by metering oil through the solenoids on this body. GEARS Magazine lists six variable pressure control solenoids and one on/off shift solenoid: a line pressure solenoid, a TCC solenoid, and PCS2 through PCS5, each tied to one clutch regulator valve. The variable solenoids should measure 3-5 ohms and the shift solenoid 16-20 ohms. In a lighter car the clutches are smaller and less forgiving, so a solenoid that is slow to respond quickly turns into a flare, a bind or a neutral feel on one particular shift.

Symptoms

• Flare or slip on a specific upshift, with RPM jumping before the gear catches
• Harsh or late garage shifts into Drive or Reverse
• Slipping or no Reverse, 3rd or 5th with DTC P0776, the PCS2 and 3-5-R circuit
• Line pressure solenoid codes such as P0960
• Gen 1 pressure switch codes like P0843 or P0873 that come back after clearing

How to confirm it is the solenoids

Run the scan tool's solenoid cleaning routine first; GEARS treats it as the starting point because debris can stick a valve that is otherwise good. Then check codes against the clutch each solenoid controls. If you have the body on the bench, GEARS warns never to put 12 volts across a pressure control solenoid; the shift solenoid can take it, the variable solenoids cannot. A plastic test plate and 45 psi of air will show whether each port flows as it should, keeping in mind these are bleed-type solenoids and all leak a little. A code can also point at a leaking clutch circuit rather than the solenoid itself, so read our shift solenoid symptoms guide and the delayed engagement guide before you commit.

Fitment

This body is listed for the 6T30 and shares its layout with the 6T40, 6T45 and 6T50, which GM covers together in its service information. The catch is the generation change. GM's PI0604C describes the 2012 move to Gen 2 controls, which removed the pressure switches; GEARS adds that PCS2 and PCS5 moved and reversed their normal state, so Gen 1 and Gen 2 parts are not interchangeable. Some 2012 small cars, such as the 1.8L Sonic and Cruze, stayed Gen 1. Check the eighth digit of your TEHCM ID (1-3 is Gen 1, B-D is Gen 2) and send it with year and VIN so we can confirm fit. For the heavier 6T45 there is a separate 6T45 pressure control solenoid assembly.

Install notes

• The solenoid body separates from the TEHCM. GEARS notes that keeping your original TEHCM means no reprogramming, which is the main saving over buying a complete module.
• Work clean. Any grit trapped between the body and its seal plate ends up in a solenoid screen.
• Fill with Dexron VI and set the level hot at the check plug; a fresh pan, filter and gasket kit keeps old debris out of the new solenoids.
• Clear adapts and drive through 10-15 shifts of each type so the computer relearns fill times.
• If the old fluid was dark and full of friction material, a solenoid body will not save it; look at the 6T30 overhaul kit.

Does this include all the solenoids or just the line pressure one?

As pictured, it is the solenoid body with all seven solenoids installed: line pressure, TCC, PCS2 through PCS5 and the shift solenoid.

Can I put this on my existing TEHCM?

Yes, the solenoid body separates from the TEHCM. Keeping your original module avoids reprogramming, as long as the generation matches.

Will a 6T40 part work in my 6T30?

The control layout is shared across the family, but Gen 1 and Gen 2 bodies do not interchange. Send us your TEHCM ID and VIN and we will confirm.

What should I check before replacing it?

Fluid level and condition, stored codes, and the scan-tool solenoid cleaning routine. A solenoid code with a leaking clutch circuit will come back after a solenoid swap.

Which fluid goes back in?

Dexron VI. Set the level with the transmission at operating temperature using the level set plug.

• 6T40 Shift Solenoid Symptoms and Replacement
• 6T40 Delayed Engagement: Causes and Fix
• 6T40 Common Problems and Fixes
• 6T40 Fluid Change Cost