Lots/most parts will interchange. I am certainly no authority on D4's but I think the outboard track frame support is different and things related to the engine controls and air intake are different.
I was hoping that my bar, blade and under carriage would be interchangeable. Oh, and I hope the winch mounts too.
The 2t is a narrow gauge and the 7u is wide, so there will be problems with the c frame. The 7u track pads will be to wide for the 2t. My 2t has 13 inch pads and there is little room to the tractor side panels . By what the parts book shows most everything will switch.My 2 cents.... WA7OPY
Not all 2T's are narrow gauge. I had one for years and it was a wide gauge.
[img]http://www.acmoc.org/bb/attachment.php?attachmentid=75721&d=1526622651[/img]
This is the 1944 D4-2T
[img]http://www.acmoc.org/bb/attachment.php?attachmentid=56101&d=1451423861[/img]
And this is my 1950 D4-7U
Yes on the winch transfer seeing that the 7U is a side tank model. Much more complicated to adapt the winch to a seat tank model. Assorted parts will interchange including complete engine assemblies. Track frames are different in that your 2T is before the large outer sprocket hub change.