Ashley P

Allison and Chrysler trans repair

16 posts in this topic

Working on 2 headaches.  1)  2003 Duramax/Allison Chevy.  Trans rarely has R.  DIC says "Range shift inhibited".   Has a couple codes for TCC circuit and ...cant remember.  USUALLY a lack of gear is caused by water intrusion into the Range/Neutral safety switch.  AND, since customer went through about 2-3 feet of water getting out of bottom land during the flood a few weeks ago, I stuck a switch on it.  No help.   Burnt fluid...changed both filters and fluid.  No help.  Checked line pressure, 200 psi, good.  At a standstill.

2)  1999 Cummins/47RE Dodge.  Customer said TCC slipped for the last 3 years, put a Jasper in it.  OK, Jasper in it, he brings it back and I ride with him....in OD w/TCC locked, rolling into the throttle makes the TCC slip about 100-200 rpm!  Command is for TCC "ON", so it's not kicking out because of the common TPS problem.  I cleaned grounds, disconnected alternator, no help.  Jasper tech said to wire the TCC solenoid ground circuit through a switch to manually ground it, thus eliminating all truck control.  Problem same.  Jasper says we'll send you a new trans.   Put it in today.  No change.   Someone here had the same problem with no solution.

Urgh.  Feel free to moan with me.

Edited by Ashley P

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Working on 2 headaches.  1)  2003 Duramax/Allison Chevy.  Trans rarely has R.  DIC says "Range shift inhibited".   Has a couple codes for TCC circuit and ...cant remember.  USUALLY a lack of gear is caused by water intrusion into the Range/Neutral safety switch.  AND, since customer went through about 2-3 feet of water getting out of bottom land during the flood a few weeks ago, I stuck a switch on it.  No help.   Burnt fluid...changed both filters and fluid.  No help.  Checked line pressure, 200 psi, good.  At a standstill.

2)  1999 Cummins/47RE Dodge.  Customer said TCC slipped for the last 3 years, put a Jasper in it.  OK, Jasper in it, he brings it back and I ride with him....in OD w/TCC locked, rolling into the throttle makes the TCC slip about 100-200 rpm!  Command is for TCC "ON", so it's not kicking out because of the common TPS problem.  I cleaned grounds, disconnected alternator, no help.  Jasper tech said to wire the TCC solenoid ground circuit through a switch to manually ground it, thus eliminating all truck control.  Problem same.  Jasper says we'll send you a new trans.   Put it in today.  No change.   Someone here had the same problem with no solution.

Urgh.  Feel free to moan with me.

#1 replace trans

#2 fix tps.

Sent from Slim's Speed Shop

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Mike, I've to the cummins customer interested in my NVG5600 that needs 6th gear.

HPR, How could TPS cause a problem when A) the command says "ON", B) I've bypassed computer control by manually grounding the TCC solenoid?

I don't see anything to condemn the Allison (yet), it's got good line pressure even when R is not working.  Could be valve, solenoid, or ? but I don't SEE faults other than TCC codes.  Allison has 200k+ with a programmer, WOT lots, pulls a gooseneck trailer like that. Amazing it's still alive.  Did I mention this is the same truck I FOUGHT with the leaking "new" injector...now that the engine is working great the trans throws a fit.

Oh, Mike, I need a can of your "learn a new skill" enthusiasm.

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Are logging real time to see the TCC slipping? I know on out autos we will allow TC to slip on a tip in like that to smooth the drive feel out. It will slip for a second or so, then lock back up.,  

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I haven't logged any yet, it appears too obvious*.  When TCC is locked at a 50 mph cruise, if you roll into the throttle the tach (and "tone" of engine") jumps about 200 rpm, mph takes a second to respond.  That 200 extra rpm remains until you back out of the throttle a little, all the time the PCM (TCM, whatever) is commanding the TCC solenoid "ON" (no PWM, just ON/OFF).

*You see the tach, hear the engine, feel the softness...it should be hooked up tight according to all others I've ever driven.  I've always been impressed (as possible w/a slushbox) with the acceleration you feel when the TCC locks behind a Cummins.

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I (and so far after a brief drive, the customer) think the Dodge TCC slip issue is fixed.  I replace both batteries.  They checked GOOD with electronic and load testers, and were just over 3 years old.  Yet, new ones seem to have fixed it. It's known that small AC voltages can cause issues, so my theory is that somehow AC voltage is being induced into the system and old battery plates are not as quick to absorb voltage spikes.

1 down, 1 to go.

mstrpth likes this

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BAM!   Fixed the Allison today.  Brought the truck and electrical "tools" home and went OLD school, layin' in the gravel.  Had seen the 'net say that TCC codes and no reverse sometimes happen together.  When looking at the wiring diagram I have NO idea why.  But, I started looking at TCC circuit...found an open in the B+...found the wire broken about 1.5' from the TCM.

Have I EVER mentioned I love MANUAL transmissions?  Of course, I've made tens of thousands of dollars because of automatics...

Edited by Ashley P

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5 hours ago, Ashley P said:

BAM!   Fixed the Allison today.  Brought the truck and electrical "tools" home and went OLD school, layin' in the gravel.  Had seen the 'net say that TCC codes and no reverse sometimes happen together.  When looking at the wiring diagram I have NO idea why.  But, I started looking at TCC circuit...found an open in the B+...found the wire broken about 1.5' from the TCM.

Have I EVER mentioned I love MANUAL transmissions?  Of course, I've made tens of thousands of dollars because of automatics...

How many hours labor does fixing that come to? :lol:

Electrical issues are a PITA to find! :yes:

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I don't even know.lol  He's been good to me, I try to be good to him.  It took me almost 2 hours (today) to find it.  And, it's only been found and temp fixed, have to get plastic conduit and tape it all back together, another hour probably to get it right.  But it's a load off me getting it figured out, STINKS when a vehicle lingers WAY after it's scheduled appointment...the other appointments still show up.

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