Transmission Issue!

[jckleewein]

I am once again having transmission problems:baby: The truck will shift find through all the gears when I am driving around town. Once I am at WOT the truck will not shift from 2 to 3, 3 to 4, and 4 to 5. Once I lift off the throttle, and get back into then it will shift into the next gear. There are no DTCs, and the fluid is full. Is it the clutches slipping?

 

[IOWA LLY]

Could be a fuel pressure issue. I have seen stock trucks (mainly LBZ's) do this if they can't hold rail pressure.

 

[JoshH]

Could be a fuel pressure issue. I have seen stock trucks (mainly LBZ's) do this if they can't hold rail pressure.

This was my first thought as well. Try logging the truck while it is acting up.

 

[Mike L.]

Fuel filter plugged? An easy place to start.

 

[jckleewein]

I thought it could be my fuel regulator, but I just logged rail pressure and everything looked excellent. I am holding rail pressure. The dual cp3 is working, because I unplugged the regulator on the pump and the truck started to idle harder. I just tried out my smallest tune and still am having this issue. This is weird!

 

[JoshH]

Does the RPM stop climbing or does it rev too high?

 

[jckleewein]

The RPM stalls at 3500 rpm and 65 mph. The ecm or tcm tune has not changed from this summer, and everything worked great then.

 

[JoshH]

How long have you tried holding your foot to the floor to see if it will eventually shift? At what RPM is it supposed to shift? Have you talked to Rob about the problem?

 

[jckleewein]

I have held the pedal to the floor for several seconds, the rpm sits at 3500. The truck is suppose to shift at 3600. I haven't talked to Rob, but I probably should. I didn't think it was a tuning issue since nothing has changed. I am re-flashing the ECM and TCM right now.

 

[othrgrl]

I know you said you already checked but I've been told that before and people were watching desired rail pressure. I just dealt with the same thing on an LMM last week, he said it wouldn't shift under WOT, went for a quick ride and saw that his rail would drain to 3,000 PSI under WOT and the truck couldn't get itself over 3000 RPM so it couldn't get high enough to hit the shift point. New filter and it shifted perfectly (and had a ton more power).

 

[Smokin LB7]

Fuel filter plugged? An easy place to start.

X2, change your fuel filter

 

[jckleewein]

Zach do you know anyone around denver that carries filters for the fass?

 

[jckleewein]

I know you said you already checked but I've been told that before and people were watching desired rail pressure. I just dealt with the same thing on an LMM last week, he said it wouldn't shift under WOT, went for a quick ride and saw that his rail would drain to 3,000 PSI under WOT and the truck couldn't get itself over 3000 RPM so it couldn't get high enough to hit the shift point. New filter and it shifted perfectly (and had a ton more power).

What I find interesting is that the command rail pressure and the desired rail pressure are pretty much identical. I can change the filter, but not sure if its the problem.

 

[Smokin LB7]

Do you still have your factory filter too, or did you remove that?

 

[jckleewein]

I still have the factory filter as well. I will get that filter form NAPA.

 

[catmenace]

I am having issues at WOT with uneven fuel delivery. There is plenty of fuel but at WOT the engine has a fast warble sound. I am thinking FPRV.

 

[jckleewein]

I am not sure what it is. I will remove the fuel regulator tomorrow to see if that makes a difference. It shouldn't since I am holding rail pressure. I am wondering if a sensor could cause this issue. The only things I have changed on the truck since this summer is that I added a fass 260, RDL manifold and up pipes, sump, fuel regulator, and SS braided fuel hose. I would think if there were debris in the fuel lines the fuel rail pressure would drop.

 

[Smokin LB7]

Is it a modded fuel regulator or an OEM one?

 

[jckleewein]

Aeromotive regulator

 

[Colt]

Given it's so cold here in Co. where is your timing in these tunes you have on>just see so many guys complaining from run issues now in winter but they have race tunes on and still might forget how cold might affect the run condition. I went way down to a tow tune for winter with the EFI. Engine's quiet and smooth even cold with alot of idle time though with what we have going. Just went over our filters tunes, and it sure makes things run nicer so far.