2011 Sierra Possible Tranny Slippage

[2011sierraguy]

I own a 2011 Sierra with 49K miles. It's A/T with 6 speeds. I've owned this truck for 1-1/2 years (used) and in very good condition.

Over the past few months, I've noticed a sensation that is hard to describe but I'll do my best. It seems as though the engine and tranny are not sinced. When I brake the truck comes to stop but the tranny downshift seems to be a few seconds later - possibly slipping. No whining or clunking sounds from tranny. Tranny fluid level is up and fluid is red.

Also, I see nothing in the owner's manual that address if and when rear diff and tranny fluid should be checked/changed. Strange!

I've owned many truck brands over the years and I have never experienced this issue. Is it just a GMC/Chev thing? My son has a 2009 Silverado that does the same thing!

A friend told me to check for a bad U joint.

Thank you.

 

[winger870]

Bump Feel/Clunk Noise at Stop or From Launch (Clean/Lubricate Propeller Shaft Slip Yoke Splines) (Corporate Bulletin Number 09-04-17-002E or later)

 

[winger870]

Also do a Google search with the number provided above to see other people with the same issue.

 

[2011sierraguy]

Thanks for your replies winger870- much appreciated. You wrote: "(Corporate Bulletin Number 09-04-17-002E or later)." What corporation - GMC?

 

[2011sierraguy]

I found that link with descriptive information. Thanks again!