I have been using my 975 with the Oppo BDP-93 for several years. I have been playing mostly Blu-rays. I just upgraded my projector to a Panasonic PT AE8000U. Everything still works great. I have used this configuration for a couple of weeks without a glitch. Two days ago I tried to play a 3D movie. I got nothing on the screen. After a few frustrating hours, I bypassed the Outlaw 975. From the Oppo player directly to the Panasonic Projector. Really great 3D. No drop outs or glitches. Perfect 3D. Today I tried another HDMI cable from the 975 to the projector. Blu-ray was great again but nothing on the screen when I tried to play a 3D movie. I wish the 975 just had HDMI switching. I really don't want video processing in my audio processor. Any ideas? Thank you anybody for reading this.

Set the Video Output for all your HDMI sources to "Native" (see page 35) then the 975 will act as a switch. I don't know if this will fix your 3D problem but its a good place to start.

I have tried all of the options in my Oppo BDP-93 player. All of the options in the Outlaw Audio 975 and all of the options in my Panasonic PT-AE8000U projector.
The 3D movie (Gravity) will start with 2D logo and then the face plate of the Oppo will display Top Menu but there is nothing on the projector screen and the player is locked. Remember that regular 2D Blu-ray's work great from the Oppo to the 975 to the projector. Remember also that 3D video works great from the Oppo to the projector. I know very little about HDMI. It appears that the Outlaw is breaking the handshake between the Oppo player and the Panasonic projector. I just noticed this item from outlaw. I says that it will make 4K work but it does not mention 3D. https://www.outlawaudio.com/products/975.html Read the red and click on TE HDS-42AVR. If 4K is passed, will 3D also pass? I have tried 3 different HDMI cables and also a HDMI repeater in line. No go.

The manual says the 975 is 3D capable so somezing eeese wrong!!

Agree with Xenon-something is not right. Can you confirm what SW rev your 975 is running? (push "INPUT" and "MUTE" simultaneously and read it off the front panel). If your 975 is a bit older maybe it needs a firmware update. If that is not it, it's probably time for a call to customer service.

I just checked the versions of my 975 MCU = 5.3, Video = 1.7 and OSD = NTSC.
I also thought that the manual said the 975 is 3D capable but I don't see that now.

I never used the 975 for 3D when I had it in my system as I don't have a 3D TV, never have. There are different types of 3D formatting. 3D TV's should support all of them. But, other devices only have to support at least one type. There's side by side and top/bottom formats, along with some others. There may be a conflict between your source device and the 975 in that they may support different formatting.
Or, I don't know what I'm talking about...

I don't know what I'm talking about either, that is why I am asking. Remember 3D from my Oppo BDP-93 to my Panasonic PT-AE8000U = perfect 3D. Running from the Oppo through the Outlaw 975 to the projector = nothing on the screen. Should the 975 work with 3D? I believe that the 975 is HDMI V1.4 which should work with 3D. My Oppo player says Blu-ray 3D on the front. My Panasonic says Real 3D on the top. My Outlaw does not have any 3D designation on it. I am now wondering about the new outlaw 976 processor. There is no 3D designation on the unit. I do not see anywhere in its online manual that it is 3D compatible or 3D ready or 3D anything. The only way to know for sure is that I may have to order it and try it. I know that I have 30 days to return it for a refund if I am not totally satisfied. Thanks for listening to my ramblings. Why am I the only one in the world with this problem. My home theater is torn apart until I work through this dilemma.

The Model 975 only supports 3D in side by side. Ensure your source device is outputting this.

The Model 976 does not have any video processing and will simply pass-thru any content, coming from a compliant source, that is within its bandwidth. As HDCP 2.0 and HDCP 2.2 are technically not backwards compatible, your 3D source may need to be connected to HDMI input 5, which is HDMI/HDCP 1.4, rather than input 1-4.

Thanks everyone. I am ordering a 976.