Welcome KarlPeakTransport.
You're in the "Turbo Diesel Topics, 2nd Generation (1994 - 2002), 2nd Generation Ram Forum (NO engine/transmission discussions)" forum. This covers 1994-1998 12 Valve engines and 1998.5-2002 24 Valve engines and most don't typically look here for issues such as "Hesitation under heavy load in hills". I would suggest an issue like this be posted in the "(appropriate engine) Engine and Transmission" forum.
We need to know what truck you have, any modifications, what transmission, what you're towing, typical usage, etc. The more info you give the more help you'll receive.