I have a 2017 GMC Sierra V8 5.7L with an 8-spd transmission and 50k miles. Last Friday I took my truck into the dealer to complete a transmission service. The dealer said that GM has not made the parts and tools yet for the technicians to complete the transmission service on the 8-spd transmission. They also said to wait to 100k miles before the tranny fluid needs changed out. Has anyone else heard of this? Seems odd that GM would put a vehicle on the road and almost 2+ years later not have dealers equipped to complete the the transmission maintenance. Personally I don't want to wait to 100k miles to have my tranny serviced.

Your title states that you have a 2016 Sierra, yet in body of post you mention 2017...you have a 2016 correct?
That is very strange that they have no parts/tools to complete a transmission service.
Have you contacted another dealer to get a second opinion about this?
Possibly the dealer you called does not have the re-circulating machine?
If another dealer also says no can do right now, contact GM owner assistance, and see what they say.
Call GMC at 1-800-462-8782
Please post back what they have to say.

Thanks for the reply. Sorry about that. My truck is a 2016. I did contact another dealer and they mentioned something about having to disconnect a thermocouple when doing the service which made it different than other vehicles, but that was it. I made an appointment to have the service done with dealer #2 this week. I contacted GMC and they did not have any information related to inadequate tooling to complete the service. They did say that you don't need to change the transmission fluid until 97,500 miles. I am still going to take mine in this week and talk to the technician to see what they say.

Every owners manual has a table of when/what to change on the vehicle.