And a D2 rear-attachment question.

The early Cats were never designed to have attachments such as rear-mounted rippers, mounted on the vertical face of the rear housing .. unlike the later Cats.
The later Cats were redesigned with heavier rear housings, more threaded bolt holes, and reinforced attachment points .. to adequately resist the massive forces applied to the rear housing, by items such as rear-mounted rippers.

To fit a rear-mounted attachment to an early Cat, requires two mounting plates on the rear of the tractor. One rectangular mounting plate has to be bolted to the vertical face of the rear housing .. and the other .. a triangular support plate .. has to be mounted horizontally, underneath the rear of the tractor, and attached to the drawbar pull point, and then bolted securely to the bottom of the vertical mounting plate.

In this manner, you are ensuring that the massive forces generated on the rear housing by the ripper, are spread between the vertical face of the rear housing, and the drawbar pull point.
The drawbar pull point is the area that is heavily reinforced on the older Cats, and is the one area, which is capable of withstanding the forces generated on the tractor rear housing, when you hit a rock or stump with a ripper.

Mounting the ripper on the track frames, via sidearms similar to the blade, is the only other alternative .. however, this makes for a 'bulkier' setup, and transfers more stress to track frame mountings and final drives.

I have seen more than one d2 that had the rear housing ripped off by someone attaching a chain to the swinging drawbar frame.

Thanks!

Yikes! I guess I'll stop chaining things to the swinging drawbar frame!

I'm not too worried about about attaching stuff to the track frames. I would think that no matter how you cut it, all pulling forces and tractor weight are transfered through the track frames.

It seems like the easiest way to do this is to get some channel and extend (U-bolt something) the blade arms back to a horizontal mounting plate behind the tractor. Then I can mount a ripper there and engage the ripper by raising the blade...

Very grateful for the rip-the-back-plate-off warning.

-Rob

Take a close, objective look at your D2. Pulling forces are not transferred through the track frames on a D2 like they are on D4 and larger. D2 uses a dead axle ahead of the sprocket, not a bearing set on the final drive. The pulling forces are entirely on the D2 final drive housings, transferred through the dead axle to the track frames (or through the gear case to the drawbar). We get away with it, but it's hard on the dead axle bushings and shaft over a long period of time.

What is the nature of the ripping job you are heading into? Ever consider a drawbar-pull two wheel ripper with a hydraulic lift?