Harmonic Vibration

[Frankenchevy]

Surprise, surprise...still there. Yet still, it is even less pronounced with the rings, but I still hear it ever so slightly. These tires are basically new, but I hear some 35s calling my name.

Anyone find it funny that I take the tires in for balancing to one America’s Tire for balancing, then to another 100 miles after the fact and they tell me they were a couple ounces out of balance? Which is correct? Lol

I’m going to set the truck aside for now and focus on my shop. I have come to the conclusion that I’ll likely have a 4L80e rebuilt while I’m rebuilding my transfer case along with some other stuff I want to do to the truck. I’ll be carrying on in my build thread and leave this one alone until the solution is found. Although, since I will be doing many things at once, it may be tough to say what eventually cures it.

Thanks for the help and suggestions.

 

[Craig 85]

Here's my last 2 cents on this. I forget what tire is on you truck, but did you ever think it is the actual tread blocks causing the harmonics? Most tires use varying sized blocks the minimize the sound of the tires. Maybe you're just down to the design of tire?

I have Falken AT3W's and you can see what I'm referring to with regards to tread block sizes. Maybe try to find someone with some oem wheels with highway tread design (photo #2) you can swap to and take a test run with them.

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[Schroedum]

Well this whole thread is almost as much fun as Gregski's on 67-72. Side note I have a similar driveline vibe on my 84 2wd that I was assuming was old U-Joints. But, I also have a L-31 and TH350...so thank you for giving me anxiety.

On a serious note is there any difference in spacing between the torque convertor and the crank of a 2pc rear main vs a 1pc? If so, could that be the source of the vibe we are feeling?