New GM 8spd tranny

cw41

Hero Member
Joined
Nov 21, 2006
Messages
529
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Location
Arizona
#1
Make
GMC
Model
Sierra 1500
Year
2018
Miles
7500
Engine
5.3 hybrid gas/elec
Has anyone had issues with GM's new 8spd tranny? This is the sloppiest shifting tranny from gm yet that I've owned, especially in the 5-15mph traffic it feels like its dropping into neutral and back to 1st or 2nd gear. Launch back and forth in and out of gear it feels like. Its not the auto-stop that I'm having issues with. While at stop sign/light, at times it feels like you have been bumped in the rear?? tach either shows autostop or idle. Didnt notice this issue when new, now just 7,500 miles 6 month old truck.
Went to gmc dealer to see and tech rode with me and noticed my concerns but no codes or updates that he could find and had no experience with my complaints. Sent me on my merry way.
I think gm has 18 tsb's on the 6 and 8 spd issues.
So, I called gmc cust assistance and see what they can do for me.
Thanks for any tips as to other gm/gmc owners that have problems with the new 8 spd. I hear that the 2020's will have a new 10 spd?? More confusion.
thanks
 

cw41

Hero Member
Joined
Nov 21, 2006
Messages
529
Likes
4
Points
18
Location
Arizona
#3
thanks bp!! I saw a tsb that they found the current tranny fluid was retaining moisture and now flushing with mobil 1 synthetic lv atf fluid part #19417577. tsb is 18-na-355