Balance Shaft: Service and Repair

Fig. 10 Balance Shaft Service:

REMOVAL
1. Remove engine.
2. Remove flywheel, then the intake manifold.
3. Remove lifter guide retainer, then the front cover.
4. Remove balance shaft drive gear bolt, Fig. 10, then the camshaft sprocket and timing chain.
5. Remove balance shaft retainer bolts, retainer and gear.
6. Using tool J-6125-B, remove balance shaft. The balance shaft and both bearings are serviced as a complete package. Use only the correct tools for bearing and shaft removal and installation. Inspect balance shaft drive gear and the camshaft drive gear for nicks and burrs.
7. Remove balance shaft rear plug.
8. Using tool J-36995-5, remove balance shaft rear bearing.

Fig. 11 Balance Shaft Endplay Measurement:

Fig. 12 Balance Shaft Front Radial Play Measurement:

Fig. 13 Balance Shaft Rear Radial Play Measurement:

Fig. 8 Timing Balance Shaft & Camshaft Marks:

Fig. 14 Balance Shaft Gear Lash Inspection:

INSTALLATION
1. Dip balance shaft rear bearing in clean engine oil, then, using tool J-36995-1, install bearing with rolled edge facing into engine and Manufacturer's markings facing flywheel side.
2. Dip front balance shaft bearing into clean engine oil, then, using tool J-36996, install balance shaft into block.
3. Temporarily install balance shaft bearing retainer and bolts.
4. Install balance shaft drive gear, then apply suitable sealant to and install bolt, tightening to specifications.
5. Install balance shaft rear plug.
6. Measure balance shaft endplay, Fig. 11. Endplay should be 0-.008 inch.
7. Measure balance shaft radial play at both front and rear, Figs. 12 and 13. Front radial play should be 0-.0011 inch and rear radial play should be .0005-.0047 inch.
8. Turn camshaft so, with camshaft sprocket temporarily installed, timing mark is straight down.
9. With camshaft sprocket and camshaft gear removed, turn balance shaft so the timing mark on gear points straight down.
10. Install camshaft gear, aligning marks on balance shaft gear and camshaft gear by turning balance shaft, Fig. 8.
11. Turn crankshaft so No. 1 piston is at TDC.
12. Install timing chain and camshaft sprocket.
13. Measure gear lash, Fig. 14, at four places, every 1/4 turn. Lash should be .002-.005 inch.
14. Install balance shaft front bearing retainer and bolts, then tighten to specifications.
15. Install front cover, then the lifter guide retainer.
16. Install intake manifold, then the flywheel. Tighten flywheel bolts to specifications.
17. Install engine in vehicle.