[bonza]

depends on what year your jeep is as the viscous clutch was changed from a bolt on style to a single nut attachment

for me I replaced the fan from a five blade to a seven blade as the latter shifts more cubic metres of air at the same rpm and also upgraded the clutch to a severe duty type

the upgraded clutch just idles when temperatures are normal, but when heat rises and it activates it locks nearly solid

specs for my model being Hayden 2791
HAYDEN FAN CLUTCH -- Severe-Duty Thermal Design, Reverse Rotation, 6.45 in. Overall Diameter, M30x1.5 Right Pilot Diameter, 1.25 in. Fan Mount Height, 3.25 in. Fan Bolt Circle, 5/16-18 Hole 4 Bolt And Nut Threads, Turns The Fan 80-90% Of The Shaft Speed When Engaged And 20-30% When Disengaged, Used With 2-1/2 in. Deeper Pitch Fans, Features Land And Groove Design With Up To 72 Square Inch Of Working Area, Larger Working Surface Provides Cooler Running And Longer Life Expectancy, And Thicker Body And Deep Finned Faceplate Dissipate More Heat, Can Be Used In Place Of Many Heavy-Duty Clutches, With Hayden's Limited 5-Year Warranty

the standard Hayden clutch for a 2005 model Wrangler is a 2771 which has the same key dimensions as the extreme duty 2791 so will fit ok

I upgraded many years ago and never have an overheat problem.

also remember the fan is only relevant when you are moving at low speed or idling for long periods in hot weather, that when mine locks up and you can clearly hear the fan roar