Squeaking Noise From Hell

I have a 1992 Chevy K1500 with the 5.7 & 700R4. I was at the Silver Lake Sand Dunes about 2 months ago when I was on the dunes and I developed a squeaking noise. And I keep it under 10mph & not past 2500rpms. She ain't a prerunner. If spark knock and belt squeal had a child from hell this would be it. It only happens in a forward or reverse gear under a load. 1/8 throttle or full throttle it doesn't happen but anywhere in between it'll knock away. While driving the moment you let off the gas or shift into neutral the noise goes away and the moment you give a little bit of throttle or shift back into a drive gear (not reverse of course) it comes back. Makes absolutely no noise in park/reverse all the way to the swirlports' redline. I have replaced the cap/rotor. The plugs and wires look good. I have had multiple mechanics and GM engineers witness and trouble shoot this problem to no avail. I have heard anything from a bad head gasket to a bad speedometer cable and everything in between so any idea is a good idea at this point

You sure it's motor related?? If it happened right after the dunes I'd check 4 things first... wheel hub bearing, ujoints (on front and rear shaft), transfer case fluid (level), and are you sure it actually came outta 4wheel drive and not stuck in 4 hi...

sent from what use to be a great country...

Fyi, you don't have a speedo cable. Check for a cracked flex plate.

magimerlin said:

You sure it's motor related?? If it happened right after the dunes I'd check 4 things first... wheel hub bearing, ujoints (on front and rear shaft), transfer case fluid (level), and are you sure it actually came outta 4wheel drive and not stuck in 4 hi...

sent from what use to be a great country...

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The truck still makes the noise even when I stand on the brakes and the truck is at a complete stop, no wheel spin, so I believe it has more to do with the powertrain and less with moving parts. I replaced the rear u joint at the diff while I was there and nothing changed. I will look into these other options thanks you

skylark said:

Fyi, you don't have a speedo cable. Check for a cracked flex plate.

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Last thing I knew all 700R4's do how else would they get the information, it is not electronically controlled? I have considered that and I will check if I end up pulling the engine which I probably will anyways due to a leaky rear main. I have already took the inspection plate off to make sure it wasn't a loose torque converter bolt and couldn't find any visible cracks while I was in there. Thank You for the feedback though

There is a speed sensor in the tailshaft on the drivers side if it is a 2wd and in the transfer case if it is 4wd.