OK we need the true experts here now

It looks like a 933 loader with the D311 engine with the compact fuel system on it.The inj. housing would be on the right side of the engine where the early D311 is on the left side. The one there looks like a 42A SN that,s with the compact fuel system on the right. The early 933 is a 11A with the big inj. housing on the left.It,s a little hard to tell from the picture you posted but I don,t think it looks big enough for a 955 & they are a 60A serial number with the compact fuel housing a D330 engine & the early one is a 12A with the D315 engine so I believe from looks that yours is a 933 42A so check the serial numbers out for sure. I did take a second look at the picture & it is possible it,s a 60A 955 so check back on the rear tran. housing above the drawbar & there should be a plate riveted there with the SN on it or if its missing look where the rivets were & they were stamped i the casting behind where the plate was riveted on between the rivet holes.Also there should be a SN plate on the left side of the diesel block just below the head usually toward the rear of the block.

This dozer should be a 933 serie 11a and you should find the serie number on left side big motor near the housing transmission cluch.

Early model 933 42A series.

Old Magnet is right, its an early 933F, 42A series with a D311 engine.

Here's my Early 42A

Yes, I was thinking 933 model with the NA D311 (second series).
Not many changes with the 933F model but the forward/reverse lever was added at sr. # 42A2106
The D320T shows beginning at sr. #42A6164 which became the G model.