Tried to determine correct belt for larger frame alternator, ordered belt that was for Duramax with 130 alternator but w/o air pump. It measures same as original. Searched more, then installed new larger alternator with original belt. Original belt is Gates 1197. 6.6 belt tensioner has much more range than 6.0 tensioner. Belt was & is keeping tensioner within marked operating range. Output wire appears to be 6 gauge. No need for other changes. Still waiting for arrival of pulley for tensioner.
New alternator, no core charge, is a pretty unit with several colors of finishes on parts. Ebay seller Total Power Parts got $72.38 for item 8237. Test paper with alternator shows it did 177 amperes. Nearly same as test #s on first alternator TPP sold me for install in 2000 Silverado 2500 6 liter. That was a trial due to belt sizing & wiring, unlike the duramax.
This is already too long, so here is a tool list. Long 1/2" breaker bar for tensioner, 5/16" or 8mm wrench for negative battery cables & 8mm air hose clamps, 15mm socket for mount bolts, grease for 3 electrical connections. Check belt & pulley bearings for wear.
New alternator, no core charge, is a pretty unit with several colors of finishes on parts. Ebay seller Total Power Parts got $72.38 for item 8237. Test paper with alternator shows it did 177 amperes. Nearly same as test #s on first alternator TPP sold me for install in 2000 Silverado 2500 6 liter. That was a trial due to belt sizing & wiring, unlike the duramax.
This is already too long, so here is a tool list. Long 1/2" breaker bar for tensioner, 5/16" or 8mm wrench for negative battery cables & 8mm air hose clamps, 15mm socket for mount bolts, grease for 3 electrical connections. Check belt & pulley bearings for wear.