Whining \'94 1500 SLE 2wd Posted this in the 88 and up section, but thought someone here may be able to offer good advice... and maybe my sob story will get me that free membership Looking for opinions on what is wrong with my '94 2wd GMC 1500 SLE. I moved from Alberta to Missouri 2 months ago (has it been that long?) and I drove down my truck towing a 16 foot single axle camping trailer (which was a BIG mistake). Now I've never had any problems towing the trailer in the past, never put premium gas in it to tow .. but here's what's happening now. Somewhere in Manitoba a huge wind/rain storm came up that continued into the Dakotas. I pulled over to sleep (finally - I think I spent 45 hours getting here, 35 driving and 10 sleeping) and in the morning when I pull out the truck is making this high pitched driveline whine once it hits about 45 mph. I didn't notice it in the windstorm the previous night and I presume something went south in the headwind. Apart from being annoying as hell (turn the radio up), I'm getting worse mileage .. like WAY worse, 6 mpg or so. Check the fluid (it's an auto) .. looks OK, doesn't smell burnt, level is OK, change the air filter at a NAPA in whatever town I pass next just in case the mileage is due to all the dust whipped up, seems OK. At this point I'm hoping it's something in the rear end rather than the trans (it's probably not engine as the whine is speed-specific, not rpm specific). So I limp into town, get settled, unhook the trailer and drive around. The whine is still there, but the mileage is much more normal. So .. Some friends are going camping in southern MO, ask if I can drag the trailer out. The truck has been OK for a while .. not counting the whine .. and it isn't that far, so I say OK. On the way out any sort of hill and I drop from 60 mph down to 35 or 40, and now the engine is KNOCKING on the hills. Stop for gas, fill it with premium and the knocking goes away. get home on premium with much fewer problems (terrible mileage aside) and it's OK to run about town. So what's your best guess? Though I was hoping the initial whine was the rear end, aI'm since leaning towards tranny. If I had to guess I'd say that the torque convertor is slipping, causing the whine and the terrible mileage. But why the knocking on my second outing? Just bad gas? I'm also willing to entertain any other diagnoses. Now here's the sob story. I was going to move down with my '72 Blazer. Even went so far as to get the new gears installed as well as a tranny cooler and an in-pan trans temp sensor. Drove the '94 because it fell into my lap (Dad got a new truck), it was too good to pass on and it would be more reliable for the trip. I also left the majority of my tools in Edmonton with my '72, anticipating some sort of mechanical problem when I get around to driving it down. So now I'm here, no Blazer, no tools, and a really annoying whine. So, if anyone has a diagnosis, I'd love to hear it, as well as any good trans shops in the area.