3X2 transmission when cold will hesitate shifting 1-2 and then sometimes 2-3 is hesitant. Once warm it shifts fine. Sometimes it will go from drive to neutral and the wrench light will come on. The only way to fix it is to shut off the engine and restart. Other times "trans brake limited" comes on. My understanding is the TISS and TOSS work the trans brake, but what about the shifting issue? Do they tell the VSM when to tell the transmission when to shift?
Showing items 1 - 11 of 11 results.
No,
They ae not serial number specific. You may need to complete a calibration once you have swapped the controller.
Do you have to reprogram the TCU if you take one off of a truck with the same engine/transmission configuration?
Rocky,
Sorry to hear the lift is still causing issues. The TISS and TOSS connect directly to the TCU. Suspect the TCU has failed or seals are leaking by inside the trans. But you said the pressure is steady throughout the temp range. Need a sister truck with same style TCU that you can swap, very expensive.
I disconnected the strobe and cleared the codes but to no avail. Until the trans temp gets to about 130, it continues to throw codes, two of them are less than commanded pressure. I've verified it's getting pressure at 270 psi. Does the TCU tell the VSM to throw a code if the 2-3 shift doesn't happen in time?
Rocky,
You may have a failing trans controller. First, disconnect the strobe light. If you have access to deleting codes, clear them. Operate lift and see if any codes return. Bad strobe light has been known to back feed the system causing havoc. Thanks.
The old TOSS was damaged and unable to be used. Yes trans brake warning pops up even after replacing the TOSS. Also when transbrake warning pops up, you can still feel the transbrake engaging. I've checked and rechecked the connections. I'm beginning to wonder if it's a bad TCU or bad VSM? Can a bad VSM or bad TCU "corrupt" a sensor? In some instances it delays in shifting before it throws the wrench code. Is there a set amount of time the VSM waits for feedback from the TCU before it throws a code? And why does the pressure on the display show 65335?
Rocky,
That code is for TOSS Sensor Direction or Direction Check Input Failure. Since you just replaced the sensor, you may want to install old sensor and see what happens. Possible failed connection at the TCU. Check all the wires from the sensor to the TCU. Possible bad wire crimp in a new harness. Verify from old harness to new that all wires are in the correct location. Does the trans brake limited code still show after replacing the sensors? If so, you may have a new sensor that is not good. Good Luck
About 2700, pressures took warm, sometimes code 522155-2 comes up.
Rocky,
Serial number would help with looking up specifics. How many hours on the lift? Could be failing seals inside trans or possible pump getting weak. You stated pressures are within specs. Did you take the pressures cold or hot? The trans brake limited, is this the only code showing? Thanks.
Thanks for the response. What I have done so far:
*Replaced TISS and TOSS and calibrated as well as the distance calibrate
*Replaced the wiring harness that connects TCU to the proportioning valves - recalibrated transmission again
*Replaced all proportining valves then recalibrated transmission yet again
* Checked transmission fluid - at the top line on the lipstick
* Checked the transmission pressures and they are good
Made sure the TISS and TOSS hex cap screws were snug.
What's the likelihood it's a fluid flow issue? It only does this when cold. If you let it warm up a good half hour it doesn't do it near as much. Could there be a stopped up filter that only let's fluid through when it's hot?
Also sometimes the LCD goes blank and only the back lighting stays on. The truck continues to run.
Rocky,
have had issues with top harness of the transmission. Wires will break inside the insulation causing havoc. Suggest replacing harness for the transmission. You may also want to complete a transmission calibration. Good Luck
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