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I drive a 2011 GMC Sierra 2500HD ex-cab 2wheel drive with a 6.0 gas engine and a six speed 6L90 automatic transmission. I have started noticing what I believe is called "shudder" from my tranny under fairly heavy acceleration or going uphill. Its just like the noise you hear when you accidently get across the white line on the passenger side while on the freeway and hit the "rumble strip". How can I be sure thats the problem and is there an easy fix?

closed as too broad by Jason C, MooseLucifer, DucatiKiller, Pᴀᴜʟsᴛᴇʀ2, dlu Aug 10 '16 at 23:53

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • I know the earlier Silverado's had an issue with the 4L60e where wear in the valve body would cause a similar issue. I don't think the 6L90 suffered from the same problem, though. I've experienced it myself in my '06 Silvy. – Pᴀᴜʟsᴛᴇʀ2 Apr 12 '16 at 15:45
  • Have you checked your transmission and motor mounts? Can you create the shudder if you put the truck in drive, press firmly on the brake and give it some gas to load up the tranny for a bit? – DucatiKiller Apr 29 '16 at 20:58
  • Does it happen at all speeds? Or only when you're going about 40-60 mph? I had the rumble strip feeling in my '97 Chevy at about 50 mph, and it turned out to be a seized U-joint in the driveshaft. I also had the valve body wear problem referred to by @Pᴀᴜʟsᴛᴇʀ2, but it didn't cause a shudder, just a check engine light and a failure to go into lockup. – Tom Penny May 12 '16 at 9:58