[titanss]

Does it Not shift at all, or does it shift and it feel like it goes in to Neutral.

 

[titanss]

im running the regular power tune, not the performance power tune with 91 octane.

when it gets up to where it should shift...its just wont, it'll run at the same RPM and just stick there. if i wait for a good 5+ seconds, it'll eventually shift.

i don't like to wait because to me, it doesn't seem right so i will either let off the gas, then give it gas and then it'll shift or what i normally do is move the gear shift over to 4, then back to D and it shifts instantly.

ETA: its been doing this before i put the BD tune on it.

Sounds like a valve is getting stuck or one of the relays in the TCM is going bad.

 

[titanss]

Maybe a gear shop ... What diameter tires are you running, and do you have the 2.94 gears or the 3.36 gears?

Mine didn't have any issue with my 33.5" M/T's but with 33.98" Terra's it does the same thing. In my case it's the gearing change from the larger tires affecting the torque converter locking it into overdrive. I would think it would happen with even smaller than 34's if you have the 2.94 gears.

Little tow gear and had 275-70-18's, 33.2" tall, on my Titan and never had shifting issues.

 

[titanss]

Even if you do not have a SES or the AT light is not flashing, there may be codes stored in the TCM. Most tranny/mechanic shops can read the codes for you, a standerd code scanner will not read the TCM codes. My tranny and mechanic have the Snap On code reader that can readr them.