Engine/Transmission (1998.5 - 2002) TC loc-up/cycling

[rgreen]

I am having a shifting problem or locup problem with my TC. It has started recently, when at the normal shift points under low throttle, it feels like the TC is locking and unlocking, locking and unlocking, cycling every 2 seconds or so. This happens at the speeds I would normally expect locup to happen, arround 40mph in overdrive off or 50mph with overdrive on. Not staying at those speeds cures the problem. Same pattern happens when either accelerating or slowing down.

Recemendations for troubleshooting and fixing the problem would be appreciatied. No changes have been made in my elec system. Factory radio etc... I know this topic has been delt with before and have searched previous posts but not found the information I need.

Thanks

 

[BWagnaar]

I just put a new Suncoast transmission in and am having the same problem. I have been playing around with the TV cable adjustment and it seemed to help. I've been working with a transmission shop in San Jose (really good shop too) and they said that on high-mile truck (mine has 195K) that the APPS sensor gets a dead spot or wear spot were they have been used a lot. Which might change the voltage that the TCC solenoid is seeing. I'm looking into this sensor right now, i hear its a little spendy though.



BUT, first off i would recalibrate your APPS. Disconnect both batts and let it sit for an hour or more and then reconnect, turn key to ON but dont start, slowly push the peddle to the floor and then slowly release. I think this is how its done, if i'm wrong i'm sure someone will let me know.

 

[rgreen]

recalibrated the Apps this AM. Have not checked the shifting problem yet. Wil be heading out

 

[John - K5AWO]

recalibrated the Apps this AM. Have not checked the shifting problem yet. Wil be heading out

There is another calibration on that APPS you need to check out. My truck has 116k abouts and the voltage from the APPS was way low. I reset it to the spec value as mentioned in the blurb I am attaching here, and the problems you mentioned plus dead pedal went away.

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</td> </tr> </tbody></table> <!-- / user info --><!-- message, attachments, sig --> <!-- message --> I'm sure someone will post a link. . but there's two recalibrations you can do for the Pedal Position Sensor... (I think one is a reset. ) I had some issues with the dead pedal. . but after the recal, I haven't had a problem. . (It was acting up about once a week. . no problems in the past 3-4 months. ) But I do have a spare under the back seat. . haha. . I'll see if I can find the tread...
Bryan

I found the Reset. .
http://www.dieseltruckresource.com/f...onlynewfaq=1

I copied this from one of JetPoilot's postings. .
resetting it using this procedure copied from DTT's website:



--------------------------------------------------------------------------------

RESETTING THE APPS SENSOR.
(ACCELERATOR PEDAL POSITION SENSOR)
2ND GENERATION 24 VALVE TRUCKS ONLY.

LIST OF TOOLS NEEDED

DIGITAL VOLT METER
# 20 TORQUE BIT SOCKET
# 1 PHILLIPS
# 10 MM SOCKET

Proper service and repair procedures are vital to ensure personal safety of those performing the repairs. Standard safety procedures and precautions should be followed at all times to eliminate the personal injury or improper service, which could damage the vehicle or compromise its safety.
Although this material has been prepared with the intent to provide reliable information, no liability is assumed in reliance of this material.

It has come to my attention that a lot of people think by disconnecting & re-connecting the batteries and stepping on the throttle it is going to reset the apps, no, that is not correct. It is impossible to adjust your apps if you do not know where it is supposed to be set at. That is why you need the voltmeter.

This is the procedure I use to re-set the apps.

With the key on, engine off you need to probe the apps wire to see where your voltage is currently set at.
The best location to probe the wire is on the PCM (power control module) which is located off the passenger side of the firewall.

· You want the C1 connector, this is the connector closest to the engine,
· You want the orange wire with the dark blue tracer which is pin # 23
· Voltage should read somewhere around 0. 5 volts,
· At this point the voltage reading does not matter, it just has to be accurately written down for later reference.

*** TURN THE IGNITION OFF ON THE TRUCK ***




Resetting the APPS Sensor cont. page 2
(Accelerator Pedal Position Sensor)
2nd generation 24 valve trucks only.

· The apps sensor is located slightly above and a little to the left of the injection pump.

· Remove the black plastic cover that is located by your injection pump.

The two screws that are holding it are plastic, do not put any downward pressure on them or you will never get them off.

· Un do the 6 - 10 mm headed bolts that hold the bracketry in place.
(DO NOT REMOVE THE CABLES)

You will notice the apps is on the back of the bracketry that you just removed, it is held in place by 2 - 20 bit screws. These screws have a little bit of locktite on them so make sure you have a good socket and gently give a little tap with a hammer before attempting to loosen. Be very careful these screws strip very easily and you only get one shot at them.

· On the apps you will find a white tag that gives you the information on what the apps adjustment should be.

· After loosening the screws you can rotate the apps both clockwise and counter clockwise to get the adjustment you need.

· The reading you took at the beginning of the process on pin # 23 should match the white tag on your apps, if not adjust accordingly.
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[JCyrbok]

only thing that I found would solve the problem (including re-calibrating the APPS, replaceing shift/lock up solenoids etc) was to install a DTT Noise Filter. Wish I would have done that first as the filter is only $45 and took all of 5 minutes to install and it immediately fixed the problem. That was 2 years ago and have had not a single problem since.



Also make sure that your grounds are good and batteries are not bad. The way I understand this problem is that the APPS gets electrical noise/interference through wire bundles that run close to each other, from the alternator (as it wears) and that this causes the APPS to not "see" the actual speed that you are traveling at and the cycling happens when the trans needs to lock up but the apps tells it not to, then to, then not to etc. increase or decrease speed and the apps either tells trans OK lock (because speed it substainatially higher than the lock up speed or not to as it lower substainsitally lower)



Funny thing (and one of the reasons I beleive the above explination of the problem) is that I had the High Idle/three cylinder TSB loaded 2 times at the dealer and it never worked. After installing the noise filter that also works flawlessly with out having to re-load the TSB software. My guess is the APPS and the ECM were not "seeing" idle as true Idle, until the filter fixed that. Just a thought.



Hope this helps some,



J-

 

[rgreen]

So far today it has been running 100% dO not know exavtly whatt fix worked. I dissconected the negatives on the batttery for 40 minutes or so and in the meantime ceaned the terminals as well as the RH connection to the APPS. Gave all a thin coating of dielectic greese while they were apart. Went through the pedal to the floor and back after all was done. and presto... Hope it stays all OK. Thanks for your help. Will get into the more detailed fix if needed later.