TC Lockup problem & Injection Pump Rebuild (related?) (1 Viewer)

[lumpy70]

Truck is a 1993 HDJ81 with an electronic A442F.

Here's the breakdown:
I had my injection pump rebuilt by a reputable shop and re&re'd by my normal guy (I just don't have the time to pull this otherwise I'd do it myself).

Since the rebuild (which went well) my torque converter lockup, which is controlled by the O/D button on my shifter, won't engage. The O/D light flashes, but due to a series of miscommunication the shop pulled the light bulb so I couldn't 'read' the code.

Thinking it was the solenoid, I replaced that, then thinking it was the ECT (I found a cheap one) I replaced that, and still no love.

So I'm wondering if there is a mechanical or electrical connection that got either missed or mis-installed on the injection pump that directly affects the O/D and the lockup of the torque converter.

I've attached the diagram from the IP that says "Governor Assy, Torque Control" which is where my brain is leading...but I poked around last night and everything looks good.

Anyone got any ideas?

 

[simonliew]

How about 22751?
Being a 93,is that a throttle position sensor?
I'm in the process of putting a pp back right now,will and that sensor seems to be in the half position when at rest.
I'll see what happen when I'm done

 

[lumpy70]

Good thought, I'll take a look. Honestly, it's hard to see the forest for the trees in there.

 

[Greg_B]

Does this thread provide any clarification? Explantion of transmission/overdrive behavior?

If the OD button is off and you are in 3rd, does the TC lockup or is there no lock up at all at anytime?

From that linked thread there is this:

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The TCM has programmed in its memory a lock−up clutch operation pattern for each driving mode (Normal or Power). Based on this lock−up pattern, the TCM turns lock−up solenoid valve on or off in accordance with the vehicle speed signals received from the vehicle speed sensor and the throttle opening signals from the throttle position sensor.
Depending on whether lock−up solenoid valve is on or off, the lock−up relay valve performs changeover of the fluid passages for the converter pressure acting on the torque converter clutch to engage or disengage the lock−up clutch.
Mandatory Cancellation of Lock−Up System:

If any of the following conditions exist, the TCM turns off lock−up solenoid valve to disengage the lock−up clutch.
(1) The brake light switch comes on (during braking).
(2) The IDL points of the throttle position sensor close (throttle valve fully closed.).
(3) The vehicle speed drops 4 km/h (2mph) or more below the set speed while the cruise control system is operating.
(4) The coolant temperature falls below 70C (158F).

The purpose of (1) and (2) above is to prevent the engine from stalling if the rear wheels lock up.

The purpose of (3) is to cause the torque converter clutch to operate to obtain torque multiplication.

The purpose of (4) is both to improve general driveability, and to speed up engine warm-up.

Also, while the lock−up system is in operation, the TCM will temporarily turn it off during up− shift or down−shift in order to decrease shifting shock.

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hth's
gb

 

[IanB]

Since the rebuild (which went well) my torque converter lockup, which is controlled by the O/D button on my shifter, won't engage. The O/D light flashes, but due to a series of miscommunication the shop pulled the light bulb so I couldn't 'read' the code.

Lets clarify something off the bat, the O/D button controls whether the transmission's top gear is 3rd (O/D off) or 4th (O/D on, O/D = 4th gear), not whether the TC locks up, which should happen in 3rd and 4th gear on an electronically controlled A442F at about 85km/h. So until your understanding and expectations are correct, you won't be seeing the behavior you expect from the transmission.

2nd, if the shop removed your O/D light in the gauge cluster, replace that ASAP so you can read the codes being flashed and properly diagnose any issues you're having.

3rd, the part # 22751 is a TPS sensor, which the trans uses for shift points, etc and will throw codes if not connected. There's also a mechanical linkage commonly called the "kickdown cable" that needs to be connected to the IP linkage, so check those 2 things and make sure they are correct.

 

[lumpy70]

Good tips everyone, thanks.

I know what I'm doing this weekend.

 

[lumpy70]

Error Code 41: Throttle Position Sensor...digging into that today.

I'm hoping it was just not connected but it's hard to tell, that wire disappears on the engine side of the injection pump.

 

[lumpy70]

Problem solved, replaced the TPS.