I tried finding the belt listed above on the NAPA website but it isn't showing up for me.
Gates K081102 is the same belt (and judging by the NAPA part number NAPA is buying them from Gates)
For tensioning, I can barely force it on by hand with no tools, but using a ratchet or breaker bar on the tensioner makes it a lot easier.
If yours is easy to install then there is definitely something wrong with your tensioner, or maybe one of your other pulleys is the wrong size or something? I mean, it shouldn't jump out of the grooves unless something is pretty far out of whack.
Do all the pulleys spin freely? It doesn't look like there is any damage to the belt back like it's slipping.
Also just to check, is the belt you have on 6 ribs or 8? The civilian trucks used a 6 rib serpentine belt, the military used 8
The one listed above is 8 ribs. And yes, I can confirm it's the correct part number for use with the Red Dot compressor. (my thread below)
So just putting this information out there in case anyone else needs it. My truck is an M1123 with the 6.5 engine and serpentine belt setup. It has the Sanden compressor for the RedDot aircon in it. That part is probably important, as the belt length does not match what the manual says it...
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