techautority.com sells the factory service manuals. There is a manual specifically for engine/drivetrain diagnostics. I believe it was $18. They also have body manuals, chassis manuals. You might have to call, because the website is not very accurate. usually they have much more available than what is shown on the website.
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01 2500 V-10 4x2 QC/LB, 4. 10, Ruenel Bumper/brush guard, RS 9000's, 2" frt springs 1500#/in, KC Daylighters, Rhino Liner, Spin Tech Muffler, DD 4" Tail, 265 BFG A/T, Lots more to come