Bicycle Mechanics - another creak question

So I've been hunting down my creaking. So far I did the following:

-the BB bearings where rough, so new BB. This is Hollow Tech I crank set, not outboard bearing type.
-while BB was out, chased and faced the BB housing.
-chain rings came off, all surfaces de-greased, bolts and BB lubed and torqued to spec.
-checked tension of wheel spokes.
-the cassette came of for cleaning and torqued back to spec.
-I have DA 7700 hubs. I took the freehub off and cleaned the mating surfaces. I didn't do anything to the freehub, as I don't know how to service it. Torqued the freehub back on to spec. New bearings and re-pack job on the hub.

The creak is still there. I narrowed it down to the rear wheel. If I swap the rear wheel from another bike, the creak is gone. I thought it might be skewers. It's not, I tried different sets. The creak can be heard by applying force to drive train while off the bike, with just my body weight on one of the crank arms. The creak is definitely somewhere in the rear wheel area.

I'm thinking it's the wheel. What could be creaking in the rear wheel? The freehub? Is that serviceable? Any ideas?

try this: if it works you will probably slap yourself. put some grease on the mating surfaces of the dropout/axle interface. sometimes its the wheel creaking against the dropout...even if the skewer is tight. hope that works... it's happened to me plenty of times.

I've done that. I cleaned them tried it with no lube and with grease. No dice. A different wheel with clean drop outs give me no creak, so that's why I'm thinking it's the wheel.

I've done that. I cleaned them tried it with no lube and with grease. No dice. A different wheel with clean drop outs give me no creak, so that's why I'm thinking it's the wheel.

I'm having the exact same issue. Different wheel, creak is gone. Had it at the LBS last night. They couldn't find it either. Tonight I'm going to put the creaking wheel on another bike to see what happens.

check spoke tension?

I checked the spoke tension. Everything was fine. I trued it up a bit for OCD sake and stressed relieved by walking on the spokes.

So here's an update. I think I found the problem... I just did about a 6 mile test and my drive train is dead silent.I'm kind of glad/mad at the same time.

I started to mess with the wheel after I put it on 3 different bikes to reproduce the noise. The whole time it was my cassette. I put my old cassette on and that solved my problem. I'm not exactly sure why my cassette was creaking. I had it off at least two times. Once to clean to try and another to rebuild the hub. I know I torqued it down to 40 Nm each time. It had 9k fewer miles that the current cassette. I rotate through 3 of the same gearing DA cassettes to average out the wear. :bang:

At least I found the annoying problem, for now....