Pull the timing chain cover and take the crankshaft position sensor trigger wheel off the crankshaft thus observing the position of the slot and the key way on the trigger wheel so that the pulse wheel may go in the correct position. Take out spark plugs because these engines have two timing chains; one is ahead, which operates camshaft sprocket on the rear cylinder head and the other is the one closest to the block and controls the camshafts for the front cylinder head. Bolt in the crankshaft pulley retaining bolt and rotate the crankshaft clockwise till the key way is aligned at the 11 O'clock position & TDC marks noted on the camshaft sprockets are lined. If not aligned turn the crankshaft one full turn and then check it again. Check the marks on the sprockets and mark the chain links if required and turn the Crankshaft to the 3 o'clock position to align the rear Camshaft sprockets in their non-operational position distancing the valves from the pistons. As for the VCT assembly, you should unbolt the mounting bolts of the assembly as well as the bolts of the timing chain tensioner of the rear chain after which, you should take out the rear timing chain from the cam sprockets. The crankshaft bolt, the chain guide/VCT assembly bolts and open the rear timing chain sprocket and take it off. Turn the crankshaft 600 degrees anticlockwise to position the front camshafts at top dead center, then loosen the front timing chain tensioner bolt and raise the front timing chain off the sprockets. If required, remove the front timing chain crankshaft sprocket from the crankshaft end. For the 3.5L engine the timing chain cover should be removed, the crankshaft sprocket bolt is fitted with the engine at TDC for cylinder No. 1. Screw in special camshaft holding tools to hold the camshafts at TDC, then remove the VCT assembly mounting screws and the primary timing chain tensioner. Scribe the chain links opposite the timing marks and then take out the primary timing chain and then the upper chain guide. If secondary timing chains and camshaft sprockets are to be removed, turn the tensioners to the left compressing them and inserting a pin to retain in position. Take the bolts of intake and exhaust camshaft sprockets but make sure that the camshaft holding tool is fitted. For 2013 and later models place the engine clockwise so that the VCT units lie parallel to the cylinder heads and then remove the valve train oil tubes and lock the camshaft with the special tools. If timing marks are concealed, painting of dots is done on the object in question as a guide during alignment. Take out the timing chain tensioner and the lower chain guides, and also the bolts fastening the VCT solenoids. Wash all components of the engine and check accidentally wounded or used components before reestablishment of the engine. Before installing the timing chain ensure the timing chain tensioners are fully compressed and locked for easy installation of the chain whereby, coloured links match index marks on the sprockets. Any of the colored links should align with index marks and tighten the timing chain guides and tensioners. Crank the engine in the normal fashion at least two full turns the look for binding and then add more oil and coolant to the crank case reconnect the battery to the starter and start the engine to look for any leakage.