Tranny wont shift unless i let off

[firewalker24]

Ok..2003 F-350 just had 6.0 built from the block up. EGR delete, 03 cam,03 computer,03 turbo,05-06 HPOP and hydros, rerouted crank case breather, arp studs, and all VC cahnges that come along.

Issue truck ran great out of the shop. Made a 6 hour round trip drive no issues over that weekend. Then I drove 10 miles down the road and stopped for a couple hours. When i got back in my truck and took off my tranny was shifting funny.

1-2 seemed to shift fine, but 3-5 would not shift unless i very slowly sped up. If i got into it it would not shift and slip or cough at higher rpm.

However as the rpms rose to about 3000, if i let off the throttle slightly the tranny would shift.

Never made a clunk or loud noise. Has not leaked, dipstick reads full, never got hot, never showed a warning light, goes into reverse and drive fine, no delay in reverse, no blinking OD lights,

please help.

[Yukon]

Firewalker any luck ? I have the exact same problem.

[firewalker24]

Originally Posted by Yukon

Firewalker any luck ? I have the exact same problem.

I found my problem was this, when they cleaned everything after putting my motor in they got water in my mass air flow sensor plug. Mass air flow was messed up causing the shifting problem. Good luck

[OCVeloMan]

Originally Posted by firewalker24

I found my problem was this, when they cleaned everything after putting my motor in they got water in my mass air flow sensor plug. Mass air flow was messed up causing the shifting problem. Good luck

Where's the plug? I'm experiencing similar issues.