P0747 - 2023 Silverado 3500HD

[KevanG]

Hoping to find someone smarter than the service guys at the dealership ...

2023 Silverado 3500HD, 59,000kms (36,600 miles). Bone stock except for an AutoSync & rubber duckie ... we're towing 99.9 % of the time. Not heavy, max combined weight maybe 7000kgs. We operate a large animal emergency response service, so vehicle reliability is critical.

 

Beginning March 17 the truck went into limp mode & threw the first P0747. Took it to the dealership, they had it for 3 days, couldn't find anything wrong.

Since then the same thing has happened 11 times, back to the shop every time; they spend days (supposedly), with no results. They refuse to pull the transmission apart to do a physical inspection. So, it's official, the service department is beyond useless. 

 

Here's what i've noticed: it only happens when the TFT is over 70C (about 160F), & after the transmission shifts from 6th to 7th. Happens with or without tow mode. Even if the TFT rises above that threshold, i can keep it from having its hissy fit by staying in 6th. Below 70/160, it's fine in any gear, any mode.

 

Any constructive ideas, thoughts or suggestions?

 

 

 

 

 

Edited April 21, 2024 by KevanG

[64BAwagon]

Contact Chevrolet and escalate the issue as much as possible. Then find out what the lemon laws are in your province and contact a lawyer who specializes. Your dealer clearly isnt taking this seriously. 

Document EVERYTHING, every failure, every conversations. Try to get your replys in writing. 

Edited April 21, 2024 by 64BAwagon