ZL1 10 speed downshifting during wot runs instead of upshifting

Anyone else have this issue or hear anything like it? Car is a ZL1 with over 700rwhp. Car was fine for a few weeks after leaving our shop with a fbo package. Runs great but all of a sudden the car started to downshift at wot. And I mean fully engaged in a pull cars flying and then right before the car is ready to upshift it DOWNSHIFTS and the rpms hit the rev limiter and scares the ever living shit out of you. It has done it in both manual mode and off a straight punch. I've scanned it and everything else seems fine. The trans has not been tuned or touched.

Any ideas?

Yikes, no one had anything like this happen. Any theory on why?

Customer have hptuners and mess with the tune? Can't say I've ever heard of this.

No HP for the customer

thats insane, does it do it both with paddle and normal shifting?

Flash engine back to stock and see what it does!! Without TCM being modded, engine can somewhat control the trans side, but not what you are experiencing..

Very odd

post the log

I'll try and post the log next time I scan it. What parameters would affect the trans tune from the ecm?

Ben, that was my thought if I can't get this figured out. Start from scratch. The only issue it I would probably end up changing the same stuff as we usually do when I start retuning it. I had the dealer check it out to see if there was a trans tune update or something. No luck.

Quote:

---

Originally Posted by JASON11WS6

I'll try and post the log next time I scan it. What parameters would affect the trans tune from the ecm?

Ben, that was my thought if I can't get this figured out. Start from scratch. The only issue it I would probably end up changing the same stuff as we usually do when I start retuning it. I had the dealer check it out to see if there was a trans tune update or something. No luck.

---

Be curious to see what vss is doing while all this is going on.