Back from camping and I have some feedback.
First, when I was running around town to get ready to camp I noticed the radiator fans come on. It was about 80 degrees out and very sunny. I wasn't moving much so I think it got heat-soaked by the hot pavement. They didn't turn back off while I was running those errands.
Second, the drive down to the campground went very well. I tried a new route that had a lot less stop-and-starts and I enjoyed that a lot. When I was starting after each stop that I did have, I was really giving it some fuel and my temps were all very good. Of course it wasn't hot, again about 80 degrees, but it was only 82-83 I think when I took the last trip and the temps were killing me. This route still took me over a test hill that was on the previous route. This hill always bothered me with our motorhome because I couldn't maintain speed up it with the 460. When I went up it last time with the truck and trailer I was disappointed that I still couldn't maintain speed and my EGTs went up to 1250 trying to do so. This time, I maintained speed and my EGTs only went up to 1100! Overall I was having a much more pleasant experience with the truck and I was on my way to actually arriving at the campground with a smile.....until..........
I got about 5 miles from the campground and when I was taking off from a light while in a town I heard a knocking noise when I gave it a solid amount of throttle pedal. So I backed off of course but all the way to the campground I kept messing with it to try to figure out what was going on. It wasn't a constant knock like a rod, it seemed to be load dependent and the closer I got to the campground the less load it took to make the noise. Once I got to the campground I popped the hood to see what I could hear. It was just plain noisy but I couldn't find a distinct noise to lay it to. I didn't want to be a nuisance in the campground so I only started it up a couple times for a minute at the sight to figure it out. I couldn't figure anything out but I did notice some oil on the back of the oil pan.
Luckily the campground is only about 50 miles from home, so we drove the Tahoe back home unloaded and thankfully it made it in one piece. As I was driving it I tried to figure it out...the thing got louder and louder, yet I could make the sound go away completely with the right application of throttle. Most of the time it sounded like a rock-crusher, but if I pushed the throttle past the quiet zone then it would knock. People would watch my drive by because I was making such a racket.
At the campground I figured it was a rod bearing (or 8) or a broken crank, but as I drove it I started to suspect either a flexplate, torque converter or transmission issue. I haven't had a chance to diagnose it further, but I will start this weekend. I was planning on yanking the engine in a couple weeks to swap a stock cam in it, but now the engine will be coming out even sooner.
I'll try to take video of the noise and see how it translates over video.
I was actually looking forward to sitting at the campground feeling content with the Tahoe in its current state...boy did that change. Oh and then I had the joy of driving the trailer home with the F150 with the straight 6 300 in it. Between the side wind, aggressive tires, dumbass Ford twin traction beam front suspension and weak engine it was NOT a fun drive. White-knuckle most of the way, but it got us home and that's the important thing.
