Hi all!

I'm new to this site. I'm hoping that your collective knowledge can help me zero-in more precisely on what year my Dad's D4 was!

I know that he bought the D4 new from Budd & Quinn in Madera CA. Unfortunately; I don't have a serial number, however the attached photos are dated “September 1950”. The photos were evidentially taken by an official Caterpillar photographer, based on their respective back labels from Peoria, IL.

1. My research tells me it's a <span style="font-family:Verdana">7U</span> based on the air cleaner location and the rear sprocket covers shape & axle cover size. Am I correct? (Per the ACMOC Serial Number Reference Manual that I just got, the “7U” started in 1947.)

Things that don't seem right for a "7U"
2. It has a side fender fuel tank vs. a seat tank. Was one tank an option over the other one?

3. If it is a 7U, I’m puzzled by the fact that the fenders seem to have an edge lip like older D4’s, vs. 7U photos with fenders w/o an edge lip.

4. When magnifying photo #1, the clutch handles appear to be straight vs. curved below the handles. This seems really weird like their levers from an older D2.

5. Does anyone know why the lights are top radiator mounted vs. side mounted (and only one front light)?

Perhaps #’s 2, 3 and 4 can be explained by someone who worked for Cat, where they know that Peoria routinely used up earlier parts from previous model versions on new versions (say making early 7U’s with say some “D4 5T” components)?

Thanks for everyone’s help with my questions!

John

PS: I hope the photos come out ok - I had to reduce them.

I think the seat orfuel tank was an option - you could have either.

Earlier D4 fenders were stamped sheet metal in the 7U series; later changed to thicker bent steel without lip.

I think the curvature of the handles (including clutch) occurred in the later 7U series, not the earlier.

Often only one light was used for ag work, and many tractors had only one light. As for being on top versus on the side, it seems to me that there were usually on the top.

I could be wrong on any and all of these.

GWH

Hello jfirebaugh,
Everything you describe would be correct for either a 6U or 7U early model.
For 1950 sr #'s for the 6U would be 3801-5700
For the 7U 7817-11309

Even appears to have the Cat rear mounted #41 hydraulic package attachment.
I'm having a little trouble telling if it is a 6U or 7U model from the pics.

After eye balling my 6U (again) I would conclude that it is a narrow gage 6U model. Fender edge almost centerline of the tracks. The 7U fender line roughly lines up with the inside edge of the tracks depending on grouser width.

OM in the picture #3 it surely looks like a 6U as the track spread looks too narrow for a 7U. I have a 6U parts book that covers from 6U9989 to 6U12781 & the fender fuel tank was optional for them under attachments. I don,t have a book any higher than this.

Hello jfirebaugh,
From the photgraphs, your tractor is definately a "6U" (narrow gauge).
I also note that you say that it has a fender mounted tank, and straight
control levers, also light type fenders.

All 6U Series D4's up until Serial No 6U 5842, and 7U 11951, ALL had straight levers, fender mount fuel tank and light fenders.

However commencing production with 6U 5843 and 7U 11952 a major design change took place about midway through the production year, the standard factory specs as standard were - Seat Tank, Curved levers and heavy steel fenders, and the fender mounted fuel tank was to dissaper for good.
Therefore your tractor Serial No must be prior to 6U 5843.

Regards

Alan T. Lewis
Christchurch
NEW ZEALAND

<span style="font-family:Arial">Boy, you guys are quick! Thanks for all of your replies - please keep them coming! </span>

<span style="font-family:Arial">When I look at my larger photos, I see that the fenders go out to about half way on the tracks. So I was wrong and it&#8217;s really a 6U narrow gauge! Cool &#8211; I just want to get it right&#8230;</span>
<span style="font-family:Arial"> </span>
<span style="font-family:Arial">Oops, I forgot to ask about the exensions on the Intake and Exhaust stacks! A Cat option, or homemade? </span>

<span style="font-family:Arial">Now, based on everybody&#8217;s input, would you guys agree that it&#8217;s likely a 1949, 1950 or perhaps a really early 1951 6U prior to S/N 5843 (depending on when the new year models arrived at dealerships)? With the photos dated Sept. 1950, I'm guessing Cat's photographer wouldn't show up a couple of years after Dad bought his D4.</span>

<span style="font-family:Arial">Thanks again so much for your help. I really appreciate it!!!</span>

<span style="font-family:Arial">John </span>

Alan as I posted above the fender tank was available on later tractors but was an option under attachments as I have the Cat parts book showing it so had to be ordered special from the factory on a new tractor.

Yes, SJ is right.
Side tank, along with early style levers, pedals and fenders with support gussets, slightly different floor boards and early seat all became attachment options. I am in the process of putting one back now similar to picture shown.

those califorina cats seem to stay real nice out that way.