What I'm about to ask is probably a normal condition, but I just want to be sure. I have a 2010 F250, 6.4, 4X4 with about 64,000 mi. I tow a travel trailer about 8000 lbs, or so. When I tow over a very steep grade (Cuesta Grade in CA, for example), it seems like there is a very loud "fan" noise noise. The fan noise seems to be running at very high rpm and appears to be separate from the engine rpm. It feels like the trans downshifts, this fan kicks on, and its loud. The first time it happened I thought something was wrong (felt like something was going to blow up), but then it stops at the top of the hill and goes back to normal. I've paid closer attention to it on successive trips over this grade and others, and it does the same thing. When it happens the engine rpm is roughly 3000, or a little less. I don't feel like there is a power loss when this happens, but it definitely feels like its tapped out and I'm pushing it as hard as it will go...I find that hard to believe.
Thoughts from more experienced folks?
Thanks
Thoughts from more experienced folks?
Thanks