Setting the timing issues

Just to clarify when you say you "can't" rotate it enough, does that mean it stops rotating or no matter how many times you rotate it, the marks never come back to being lined up?

Yes, it is normal. Eventually it would come back, but it will take many rotations. As long as you had it correct when it went together, it will be fine.

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I'm going to provide timing directions. Just confirm this is how you had it. The attached pictures correlate with the directions.
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2011 GMC Truck Acadia AWD V6-3.6L
Components
Vehicle Engine, Cooling and Exhaust Engine Timing Components Timing Component Alignment Marks Locations Components
COMPONENTS
Timing Chain Alignment Diagram

Camshaft Position Actuator Timing Marks

pic 1

1 - Right Intake Camshaft Position Actuator Identifier
2 - Right Intake Camshaft Position Actuator Right Side Timing Mark - Triangle
3 - Left Intake Camshaft Position Actuator Left Side Timing Mark - Circle
4 - Left Intake Camshaft Position Actuator Identifier
5 - Exhaust Camshaft Position Actuator Identifier
6 - Exhaust Camshaft Position Actuator Right Side Timing Mark - Triangle
7 - Exhaust Camshaft Position Actuator Left Side Timing Mark - Circle

Stage One

pic 2

1 - Left Intake Camshaft Position (CMP) Actuator Timing Mark - Circle
2 - Left Intake Secondary Camshaft Timing Drive Chain Timing Link
3 - Left Exhaust Secondary Camshaft Timing Drive Chain Timing Link
4 - Left Exhaust Camshaft Position (CMP) Actuator Timing Mark - Circle
5 - Left Secondary Camshaft Timing Drive Chain
6 - Primary Camshaft Drive Chain Timing Link for the Left Primary Camshaft Intermediate Drive Chain Sprocket
7 - Left Primary Camshaft Intermediate Drive Chain Sprocket Timing Mark for the Primary Camshaft Drive Chain
8 - Left Primary Camshaft Intermediate Drive Chain Sprocket
9 - Left Secondary Camshaft Timing Drive Chain Timing Link for the Left Primary Camshaft Intermediate Drive Chain Sprocket, behind hole in sprocket
10 - Left Primary Camshaft Intermediate Drive Chain Sprocket Timing Window for the Left Secondary Camshaft Timing Drive Chain Timing Link
11 - Primary Camshaft Drive Chain
12 - Primary Camshaft Drive Chain Timing Link for the Crankshaft Sprocket
13 - Crankshaft Sprocket Timing Mark
14 - Crankshaft Sprocket
15 - Right Primary Camshaft Intermediate Drive Chain Sprocket
16 - Primary Camshaft Drive Chain Timing Link for the Right Primary Camshaft Intermediate Drive Chain Sprocket
17 - Right Primary Camshaft Intermediate Drive Chain Sprocket Timing Mark

Stage Two

pic 3

1 - Left Intake Camshaft Position (CMP) Actuator Timing Mark - Circle
2 - Left Intake Secondary Camshaft Timing Drive Chain Timing Link
3 - Left Exhaust Secondary Camshaft Timing Drive Chain Timing Link
4 - Left Exhaust Camshaft Position (CMP) Actuator Timing Mark - Circle
5 - Left Secondary Camshaft Timing Drive Chain
6 - Primary Camshaft Drive Chain Timing Link for the Left Primary Camshaft Intermediate Drive Chain Sprocket
7 - Left Primary Camshaft Intermediate Drive Chain Sprocket Timing Mark for the Primary Camshaft Drive Chain
8 - Left Primary Camshaft Intermediate Drive Chain Sprocket
9 - Left Secondary Camshaft Timing Drive Chain Timing Link for the Left Primary Camshaft Intermediate Drive Chain Sprocket, behind hole in sprocket
10 - Left Primary Camshaft Intermediate Drive Chain Sprocket Timing Window
11 - Primary Camshaft Drive Chain
12 - Primary Camshaft Drive Chain Timing Link for the Crankshaft Sprocket
13 - Crankshaft Sprocket Timing Mark
14 - Crankshaft Sprocket
15 - Right Primary Camshaft Intermediate Drive Chain Sprocket
16 - Primary Camshaft Drive Chain Timing Link for the Right Primary Camshaft Intermediate Drive Chain Sprocket
17 - Right Primary Camshaft Intermediate Drive Chain Sprocket Timing Mark for the Primary Camshaft Drive Chain
18 - Right Primary Camshaft Intermediate Drive Chain Sprocket Timing Mark/Window for the Right Secondary Camshaft Timing Drive Chain
19 - Right Secondary Camshaft Timing Drive Chain Timing Link for the Right Primary Camshaft Intermediate Drive Chain Sprocket
20 - Right Secondary Camshaft Timing Drive Chain
21 - Right Exhaust Camshaft Position (CMP) Actuator Timing Mark - Triangle
22 - Right Exhaust Secondary Camshaft Timing Drive Chain Timing Link
23 - Right Intake Secondary Camshaft Timing Drive Chain Timing Link
24 - Right Intake Camshaft Position (CMP) Actuator Timing Mark - Triangle

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Let me know if this helps or if you have other questions.

Joe