68rfe guru's help needed

P

proctors garage

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Oct 22, 2011
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I have a 07 3500 that I built the trans in that is kicking my tail. Trans is about two weeks old but about a week after it started locking and unlocking TCC. with my scan tool connected the LR/TCC solenoid looks to be commanded to by the TCM. The trans works good other than this. If I keep light steady throttle it will stay locked but apply any load at all and it will unlock. Looking at the engine speed to turbine speed it is not slipping.I have checked voltage at TCM on LR/TCC control and the TCM is removing voltage from LR/TCC solenoid. I have checked tcc on and off pressures. With tcc on pressure ramps in through partial EMCC to full EMCC and at full lockup the pressure holds at 150psi with 0psi on tcc off port. For whatever reason the tcm is commanding my problem to happen and I am running out of ideas. The voltage on LR/tcc solenoid control drops slightly as the engine is loaded and rises if I back off throttle this seems kinda strange to me.
 
The only advice I know to give you is to call the kids at Firepunk and ask them if they have a minute to chat with ya. Lots of brains in that facility.
 
The 68's have issues with the valvebody's warping and causing fluid leaks which can cause strange symptoms.
 
Valve bodies are on backorder at Chrysler. I had a low mileage unit I robbed from when I built it. I swapped t.v. this morning with no change same troubles.
 
You can buy the gas vb, which is not on back order, swap some stuff from your original vb and all is good. Basically you use the plates and hard parts from the gas vb and moving parts from diesel vb. Give Firepunk a call they did this on mine and it has been good for 8k now.
 
Do you have a TCM tune in the truck? H&S overdrive software? I wouldn't say we're 68rfe guru's as we have one in the shop right now giving us all kinds of TCM related problems also but we keep narrowing down the options, one step at at time.
Have you tried to reflash TCM with H&S(if applicable)? I assume no DTC codes since it's just following the commanded signal?

Lavon
 
No tunes in the tcm all stock. It finally has a gear ratio error code for 6th. I finally got my hands on a new vb and I'm thinking I might replace the pump to. I tried another tcm today it was exactly the same. I went ahead and pulled through transmission back out I wanted to look into it again and reevaluate it ,and re check the valves. I'm definitely going to replace vb. The truck is deleted with a smarty.I have taken movies of tcm and ecm data and have been studying that nothing seems to be out of order. I have began to wonder about a ecm problem. Looking at a wiring diagram I don't see a direct wired in link as far as ecm inputs to tcm those must come through can bus.
 
I think the 6that gear ratio code is most likely because of tcc. I have changed speed sensors and pedal although there data seemed fine but that didn't change it.
 
Torque converter is bad, its not holding under power and that will also cause 6th ratio code
 
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