4L30E Tcc Solenoid 1990-1999

If you own a 1990-1999 Isuzu Trooper, Rodeo or Passport, a Honda Passport, a Cadillac Catera or a BMW 3 or 5 Series with the four-speed 4L30E, and the engine now runs higher RPM at highway cruise, the converter never seems to lock, or reverse goes soft and neutral when the truck is cold, the torque converter clutch (TCC) solenoid belongs on your short list. This is the pre-2000 on-off style TCC solenoid with the bracket and side connector, sold new as a single solenoid.

What the TCC solenoid does in a 4L30E

GM's 4L30E specification sheet describes the TCC solenoid as a simple two-way on-off valve. When the control module grounds it, the solenoid opens and sends signal oil to the converter clutch valve in the pump, and the converter locks up. In 1990-1999 units the lockup is either fully on or fully off; there is no modulated slip. That changed for 2000: Transmission Digest reports that 2000-and-up Trooper and BMW units moved to a pulse-width-modulated TCC that needed a different PWM solenoid and a reworked pump, while Rodeo, Passport and Catera stayed with the on-off design. So a 2000-up Trooper or BMW does not take this part; use our 4L30E TCC solenoid for 2000 listing and match it to your unit.

The 4L30E also does something unusual with this solenoid. TCC signal oil is routed to the spring end of the reverse-lockout valve so the transmission cannot go into reverse while the converter is applied. A solenoid that leaks or stays partly open feeds that circuit when it should not, and the result is a reverse complaint, not just a lockup complaint.

Symptoms of a failing 1990-1999 4L30E TCC solenoid

• No converter lockup at steady highway speed, with cruise RPM a few hundred higher than it used to be and fuel economy down
• Lockup that cycles on and off or shudders as it applies
• Slipping or neutraling in reverse, or a feeling that the converter clutch starts to apply and then the truck neutrals in reverse, usually worst when cold
• A stored TCC solenoid circuit or performance code; on 1996-up OBD-II vehicles read the exact code with a scan tool before ordering
• A missing filter screen on the tip of the old solenoid when you pull it

How to confirm it before you buy

Start with fluid level and condition, then check solenoid resistance at the connector and again on the bench; our guide on testing a transmission solenoid with a multimeter walks through both. Apply 12 volts and listen and feel for a crisp click, and blow through it to confirm it seals when off and flows when on. If the solenoid passes, the problem may be in the converter itself; the torque converter clutch shudder diagnosis guide covers how to separate a converter fault from a hydraulic one. Ed Lee's Transmission Digest article notes that when this solenoid fails the screen in its end is very often gone, so if yours is missing, fish it out of the auxiliary valve body before installing the new one.

Fitment

This listing covers the 4L30E for 1990-1999. That includes the Isuzu Trooper, Rodeo and Passport, the Honda Passport and Acura SLX twins, the 1997-1999 Cadillac Catera and BMW models such as the E34 525i and E36 328i that used the 4L30E. The adapter case, center support and spacer plate differ between BMW and Isuzu versions, and the 1990-1993 Isuzu trucks have their own control strategy, so compare the bracket shape, connector and screen tip on your old solenoid to the photo, or send us your year and VIN and we will confirm before it ships. More parts for this transmission are in our hard parts section.

Install notes

• Drop the pan, remove the filter and unbolt the solenoid from the valve body; note the bracket position so the new one seats the same way.
• Lube the new O-ring with clean fluid and make sure the screen is in place before installing. Do not overtighten the bracket bolt into the aluminum valve body.
• While the pan is off, replace the filter and pan gasket; our 4L30E filter and pan gasket kit fits BMW applications. If more than one solenoid tests weak, the 1990-99 4L30E solenoid kit replaces the full set at once.
• Refill with the Dexron III-type fluid GM specifies for the 4L30E (or the current fluid your owner's manual lists), check level hot, then drive through several lockup cycles at 45-60 mph and confirm RPM drops when the converter applies.

Will this TCC solenoid fit my 2000 or newer Isuzu Trooper or BMW?

No. Starting in 2000 the Trooper and BMW 4L30E went to a pulse-width-modulated converter clutch with a different solenoid and pump. This part is for the 1990-1999 on-off design. 2000-up Rodeo, Passport and Catera kept the on-off pump, so send us the year and VIN and we will confirm.

Can a bad TCC solenoid cause reverse problems on a 4L30E?

Yes. TCC signal oil also acts on the reverse-lockout valve, so a leaking or sticking TCC solenoid can cause slipping or neutraling in reverse, especially on cold mornings. Test the solenoid before you blame the reverse clutch.

How do I test the TCC solenoid?

Measure resistance across the terminals with a multimeter, then bench test it with 12 volts to confirm it clicks, seals when off and passes air when on. Also check whether the screen in the tip is still there.

What fluid does the 4L30E use?

GM's specification sheet lists Dexron III for the 4L30E. Many vehicles now call for a licensed Dexron VI or the fluid named in the owner's manual, which is backward compatible. Check the level hot after the install.

What should I replace along with the TCC solenoid?

Since the pan is off, replace the filter and pan gasket. If the other solenoids test weak or the transmission has high miles, a complete 1990-99 solenoid kit is the better buy.

• How to Test a Transmission Solenoid With a Multimeter
• Torque Converter Clutch Shudder Diagnosis
• Bench Testing Transmission Solenoids
• Torque Converter Stall Test and Lockup Diagnosis