In the past several years, I've slowly as budget allows, been bulletproofing my '05 F350 6.0 SWR with 4.30 gearing with BPD products. The most recent upgrade I performed was switching out the OEM fan clutch to the BPD 7.3 mechanical fan clutch. So far I've enjoyed my coolant/oil temps running 10 degrees less or more from what I was running before when towing. Now as my post states, with such an aggressive fan clutch I noticed when I'm in tow/haul mode and using engine braking, my RPM's will rev to slow me down and the fan clutch is fully engaged at this time. I does its job in slowing me down but the noise of the clutch is very loud since I'm assuming the clutch is fully locked. Will this increase wear on my belts and pulley? I'm asking because I'm noticing a squeal coming from inside the hood when I'm engine braking only and RPM's over 3k. Anything under 3k RPM and I don't hear the squealing. It's never down this before. Not even when I WOT the truck only when I'm engine braking. I replaced both belts at the same time when I installed the mechanical fan almost 2 years ago. Both belt tensioners were in good shape at the time and never allowed the belts to slip. I replaced my belt tensioners approximately 6 yrs ago when I replaced my belts prior to this installation. My plan is to replace both tensioners, belts and any worn out pulleys, if needed. However, will having such an aggressive fan clutch that is locked more often wear down my pulleys and belts? Also, my RPM's will run higher when engine braking as I'm running 4.30 gears.