Allison shift problem

[calgator73]

Yesterday...1/4 tank of fuel transmission hung on 2-3 shift during WOT up an on-ramp. Had to let off to shift.

 

No tune...only "mod" billet bleeder screw. FF only 12k miles 65% life.

 

Thoughts?

 

Sent from my SM-G930P using Tapatalk

[calgator73]

Any ideas?

 

Sent from my SM-G930P using Tapatalk

[Chris2087]

I have an idea, perhaps during WOT, the TCM wont allow an upshift until the RPM and torque are within a set range.

[Peterd]

Drive it don't beat it and all will be fine

[calgator73]

I have an idea, perhaps during WOT, the TCM wont allow an upshift until the RPM and torque are within a set range.

That's what i was thinking based on some reading. Looks like clogged fuel filters, vacuum leaks at the filter head and low fuel with some kind of fuel tank mod can cause it. With full tank couldn't duplicate.

 

Sent from my SM-G930P using Tapatalk

Drive it don't beat it and all will be fine

Something's up though

 

Sent from my SM-G930P using Tapatalk

[calgator73]

That's what i was thinking based on some reading. Looks like clogged fuel filters, vacuum leaks at the filter head and low fuel with some kind of fuel tank mod can cause it. With full tank couldn't duplicate.

 

Sent from my SM-G930P using Tapatalk

Something's up though

 

Sent from my SM-G930P using Tapatalk

Full tank of diesel had no issues. Less than a quarter tank I have issues.

 

Sent from my SM-G930P using Tapatalk

[SMiller]

Drive it don't beat it and all will be fine

Loaded pulling up on ramp...

 

Truck should shift just fine at WOT empty or loaded, sounds like a TCM issue.