Just got a call from the shop. He said he found it . The joint in the drive shaft is bad. He said the case looked good and the shaft tested good on the machine but he rotated it and found it.
I couldn’t test it by pulling the rear cause the front auto locker wanted to push me in a ditch.
We’ll see.
That’s good news. I hope he’s not the type that finds one thing wrong, stops there and assumes everything else is ok. When I replace a ujoint on a driveshaft I rebuild the whole shaft since all the joints have the same mileage and what’s the point of pulling it again 3 months later.
I had a strange flutter sound that was due to a bad centering yoke on the rear driveshaft. It was especially bad on startup under load in 1st and 2nd, and with speed it quieted down but was still there. Sounds similar to yours.