You can get the 4 volume printed GM manuals on Ebay. They shouldn't cost more than $300 for a full set. You can find em for between $200 & $300 with patience. The SUV/Avalanche and Silverado/Sierra are different sets. Well worth the money and you can re-sell them when you buy another truck.
Eric O posted this video on where to find aftermarket service info.
http://youtu.be/L1FxoQI_Fw4
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1959 M35A2 LDT465-1D SOLD
1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8
RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.