strange noise between 55-60 mph

My 93 G20 van, has a L60E tranny I think, makes this noise while cruising around 55-60 mph, it does it when I speed up just slightly from 55, I can then let off the gas and it will quit, then doesn't make that noise when I step down on it, to the floor, it will accelerate just fine , no noise until I let off the gas and it levels out, then the noise resumes.
Does this sound like the torque converter clutch to anyone, if not that then what do y'all think it could be??
Many thanks to all,
Frank aka Crazyhorse357

Check for dry and worn U-Joints. Rust around the caps is a good indicator.

Thanks TM67,
I'll do that, I'm so old that sometimes my mind goes blank when it comes to a problem, thank God for young guys like you and this forum, or I wouldn't get anything done.
Thanks again, really appreciate your response.

If it does it in drive and OD check your rear end bearings and ring/pinion gear setup.

http://www.differentials.com/diagnose.html

http://www.differentials.com/diagnose.html