'05 6.0 f250, studded, deleted, injectors, straight piped, tuned. she hot, 500 rwhp. SCT flash x3 tuner and i got innovative tunes on it. xtreme street (120hp) is the hot one and its insane. anyway, in the hot tune, from a stop, i hit the gas and i got power and boost, but truck doesnt go anywhere. trans isn't fully engaging i guess. but anywhere else I have total power. that's the first symptom. Secondly, I holds me in gear when I come off the throttle over a certain speed(or in a certain gear) effectively giving engine braking which isnt good. Thirdly, it hunts at idle. also the shift from 3rd to 4th is longer and the revs go up and then jump down when it grabs 4th. It only does the power and boost but no movement thing in the hot tune, but hunts and stays in gear in any tune including stock. any help? I think I've narrowed it down to a controls issue. thinking TCM is bad/confused, and not fully engaging clutch packs and therefore bogging the engine. Then it holds me in gear in (i think 4th). then for the hot tune problem, its starting me in a higher gear and using clutch packs and torque converter to get me going. This is my thinking, and my dad thinks it's valve body stuff, which it totally possible on the 5r110w. We are not afraid to tear it apart ourselves, my dad's built plenty of transmissions before. let me know what y'all think.

 

I don’t know how tuning impacts this, but what transmission codes are present?

 

well that's the thing, I don't have any codes at all, according to my SCT x3

 

You need to try a different tool to read codes. SCT is good for gauges, but isn’t always good at codes.

 

When troubleshooting a problem, first step is always go back to stock tuning.

 

I unplugged the Mass airflow sensor and got no check engine light but it seemed to fix the hunting and cleaned up the shift from 3rd to 4th. I was able to drive and shift fine without a maf sensor and still got no check engine light. The reason the maf sensor was an idea is because it reads load on the engine by measuring air intake, which could cause the tcm to get bad signals and not shift properly. Also, I learned that limp mode in the 5r110w can result in the tcm defaulting to 5th and reverse only, which sounds like my problem with the hot tune. The reason limp mode could only be engaging in the hot tune is because I'm demanding higher shift pressures. This leads to a bad solenoid causing limp mode, which only acts up under high shift pressures. This is all i got out of today, so either shoot down or confirm this stuff, i need help real bad

 

also the no check engine light leads me back to the pcm being bad, which houses the ecm and tcm. this explains just about everything so, there's that too

 

You need to find the codes stored. Codes don’t always cause a check engine light.
There is an inexpensive app called Forscan and then you need a wireless adapter to plug into the obd port.

Forscan will read all the codes for you.

 

How does the trans fluid look?

 

full, red, and clean

 

Buy a decent code checker B4 you spend any $$ on repairs ! This one will also read live data (with truck running).

 

well, new info. like i said, there's no codes, took it to a place and they did some fancy scan. only codes were abs, egr, and glow plugs 6 and 8 are bad, and other minor junk. the truck does something every now and then where it cranks but no start, and the solution has been unplug the icp sensor, and it works every time. We also discovered that unplugging the icp sensor fixes the hunting issue. I can drive without an icp, and it throws a code and check engine light only after I drive it, then shut it off. Clear the code, plug it back in, no check engine light. So computer seems to be working. I still don't know why this is the solution, but it hints at something else in the fuel system. Also, pretty sure I just lost a solenoid, either 4th or 5th gear, i'm leaning towards 5th. that's what I think it going on, and that's the progress i've made. The truck is still driveable and I just cannot figure this out, and it's very irritating, and I'm sure all of you know the feelings. any advice on what to do next?

 

Why not replace the ICP sensor?

 

I already did that. might've just been a bad one, I put the old one back in to see if that did anything. I'm trying to rule the icp out so I can trace it back to an inevitably bigger issue.

 

Could be an ICP sensor harness issue also, but usually if unplugging the ICP sensor resolves surging type symptoms, then it was a bad ICP sensor.