RomeK/G would this be an original ripper box fitted? it does look very similar to todays style ripper unit fitted to graders, obviously smaller is size, possibly closer to a 12g size machine? Yes I wish I had one on my machine. cheers

Busso20,
It is a cat No.4 ripper, built for the D4's. I'm not certain it was available during the U series production, but most certainly from the mid 60's through to the end of the D4e production run.
Was pretty much standard on most D4D and E's destined for this part of the world.

Glum, thanks for the info I will keep an eye out for one, cheers

Here's the one I've seen on a D4 dozer for sale here in Melbourne Australia:

 

Hi, Folks.
If my memory serves me rightly, Cat did not make a ripper for the D4s until the D4D 'coz their back ends were not designed for it. They were considered to be an agricultural tractor for drawbar work and the bulldozer was simply an attachment. That changed with the D series.

That said, I have seen some pretty sturdy rippers fitted to earlier D4s, probably the strongest of which was fitted to a 2T and placed ZERO load on the back end other than the final drives having to pull it 'coz it was mounted entirely direct to the track frames and used the normal blade rams minus the blade for lifting and lowering. A very neat piece of work.

Just my 0.02.

The proper way to mount a ripper on these earlier tractors was to take the pull through to where the drawbar pulled from, usually a couple of long high tensile rods threaded at the back where they came through holes in the bottom of the backing plate. When the nuts were pulled up tight, all the load went through to under the transmission case where the drawbar pulled from.

Wombat

The 58Dxxxx  #4 Cat ripper application is for the 7U and 955 - 12A Traxcavators but I see no reason it could not be mounted to earlier model D4's. As Wombat states the bulk of the pulling load is transfered
to the forward drawbar mounting. Kind of a rare item to find now and was more common on the Traxcavator.
I copied the same design when constructing the 3-pt hitch for my D4 "U" model.

Great photos, thanks! Was looking for something like this for my D4-7U.
Do you have drawings/dimensions for it by any chance?

Sorry no drawings or dimensions. Kind of a one off fabrication. I do remember leaving about 1/8" space for shims between that lower bracket and the rear case mounting plate.