Tech 101

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2004R Lock-up

The 2004R Lock-Up is an Electric function. The transmission has nothing to do with this function. I will outline how to diagnose the problem. Assuming each check is ok go to the next. This procedure will correct 99% of lock-up problems. If you have mixed and matched Valvebodys Make sure you used the correct separator plate.

Save yourself some time. Before assumptions USE A SCAN TOOL. Verify that the ECU is commanding lock-up. If the ECU does not command lock up the converter will not lock. Be 100% sure the ECU sees the pressure switches and goes in to lock up mode before moving on. The following checks will not cure the problem if the ECU is not commanding lock up. I have spent hours on the phone only to find the Chip had the lock up function deleted or was mis-programed or ECU had a problem.

Check to be sure you have 12volts with Key on at the 3 or 4 prong connector on the drivers side of transmission. The 2004R has a constant 12 volts and the factory ECU grounds the circuit to operate the TCC solenoid. The pin location on the connector is pin A. That Pin should have 12 volts with key on. If no voltage you will not have lock-up. The Pin A comes threw one of the brake pedal switches. THE BRAKE LIGHT SWITCH HAS NOTHING TO DO WITH LOCK UP. One of the ECM fuses is the power source for the 12 volt supply. Check the adjustment of all the pedal switches.

Once we know we have 12 volts at Pin A find the ground in the connector. There should be 3 other wires in the 4 prong and 2 in the 3 prong connector. These are for 1 or 2 pressure switches and one for grounding of the TCC solenoid. You can ground these one at a time till you hear the click of the solenoid. Don't be afraid you will not short anything once you know where the 12 volt supply is. If you do not hear the solenoid click then stop and replace the solenoid.

If Solenoid clicks then make a temporary grounding wire so car can be driven. When driving the car when transmission shifts to 2nd gear the converter should lock immediately. If converter locks. Then the problem is in the circuit of the car. You will need a scan tool. The scan tool will verify that the ECU receives gear signal from the pressure switches. If no signal from pressure switches replace both of them. If the ECU does see pressure switches problem is in the ECU or wiring of the TCC circuit.

If solenoid clicks and test drive converter does not lock on the 2nd gear shift. You will need to remove the pan. Remove the TCC solenoid. Check to be sure the seal on the solenoid is in good condition. The next check while we are here is to look up into the pump in the location where the TCC solenoid has been removed. You will see a sheet metal round plate with a hole in the middle held in place by a snap ring. Above this is the TCC valve. Take a small crew driver or pick and stick threw the small hole. Push up on the valve be sure that it travels up into the pump and returns to the plate. Do this several times. If this valve is sticky you will have no lock up. If valve moves freely and o-ring on solenoid is in good condition. Take a check ball or something similar and drop in the opening of the TCC solenoid and re install. Put pan back up and test drive car. If trans lock up on 2 gear shift then stop and replace the TCC solenoid.

If converter does not lock while test driving with check ball in solenoid. You have one of the following. Faulty Torque converter, Converter feed orifice in pump is plugged (Not a common issue), Wrong separator plate for valvebody used (very rare), Faulty pump (extremely rare)

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Converter Stays locked

Easy Test is to shut car off and let sit for a few minutes. Un plug the connector on the side of the trans and test drive. If converter locks on 1-2 shift. You have a faulty TCC solenoid or you can have debris in the TCC solenoid blocking the bleed hole. If converter stays locked after the few minutes of engine off time you have a faulty converter or the Converter Clutch Valve in the pump is stuck.

If converter does not lock replace the TCC solenoid.

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TV (Detent) Cable Adjustment

Critical to the life of your 2004R or 700R4. The TV cable raises line pressure in the transmission and its adjustment is vital to the life of the transmission. The following assumes correct throttle linkage geometry used in a fuel injected or application where the transmission was used from the factory.

Most Factory cables have an automatic adjustment. You push the button in on the side of the cable. While holding the button depressed pull the cable housing toward the firewall as far as it will go and release the button. Now depress the pedal and the cable should ratchet into place. To check your adjustment open the throttle all the way by hand and check to be sure there is no play in the cable. Be sure its tight. This is full TV setting. If the trans shifts very hard at this setting you can back off the cable a couple of clicks. If you back off the cable from full TV and it softens the WOT you have gone to far.

Aftermarket cables do not have the auto adjustment. You will adjust them by simply releasing the clip and moving the cable. Check WOT setting to be sure you are at Full TV as a starting point. Adjust from there.

A pressure gauge should be used when the 2004R or 700R4 has been used in a carb conversion.

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TH200-4R Pressure Test Chart

To perform a pressure test on your 2004R is not hard and can supply lots of info if you are having a problem. You will need a 90 deg. fitting 1/8" pipe to -4. You will also need a pressure gauge that goes to 300 psi.

The pressure tap is located on the left side of the transmission above the linkage. Typical pressures of a healthy 2004R listed below. I have also listed the minimum required to for decent transmission life. The test should be performed with engine RPM slightly elevated to around 1200 RPM or more. Full TV requires the TV cable to be pulled out as far as it will go.

Dont get too hung up on the pressures in Park as some VBs do not boost in Park and some do. The other gears are very important.


Excellent pressureMinimum
GearNo TVFull TVNo TVFull TV
P90 psi275 psi70 psi225 psi
R230 psi230 psi200 psi200 psi
N90 psi275 psi70 psi225 psi
490 psi275 psi70 psi225 psi
390 psi275 psi70 psi225 psi
2250+ psi250+ psi225+ psi225+ psi
1250+ psi250+ psi225+ psi225+ psi

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TH200-4R Starts in 2nd Gear

2nd Gear starts are a common complaint on the 2004R. In most cases the problem is caused by the TV cable adjustment. This is a very easy check. Drive the car to reproduce the problem. When the car feels like its taking off from a dead stop in 2nd stop the car. Move the shifter into neutral and then shift back into overdrive. If the car takes off in 1st your TV cable adjustment is too tight. If the car takes off in 2nd consult your builder.

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Caution!!


The TV cable has a very small area of adjustment. To fine tune your adjustment a pressure gauge should be used. If your 2004R was used for a carb conversion you should use pressure gauge to verify your adjustments to be sure the geometry is correct. No magic spring will correct geometry.Click the following link to open a PDF file with easy to read and follow instructions. TV Cable Adjustment Link  »  PDF

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