d6 9U Serial Number Alternate

yes it is stamped in the frame on back of it top left corner looking towards the engine left side sitting in seat

JW is not too clear as it,s location but it is on the back rear main housing above the drawbar and if a plate is missing Cat always stamped it in the casting of engine where the plate was or where the rear plate was above the drawbar.If plates are missing usually you can see either the rivets there yet or the holes where they were riveted.

Vanlon - The S/N tags are located in two positions on the D6 9U .. one is located at the left upper rear of the engine block, behind the pony start controls .. the second tag is located on the vertical face of the main rear housing at the left upper side. These tags should read exactly the same.

If they are different, the tractor has had the engine block replaced with an engine from another Caterpillar tractor, power unit, genset or marine engine.
Alternatively, the tractor has been rebuilt using parts from two tractors or a multitude of parts sources.

The tag is a small brass or aluminum tag about 1" x 2". As SJ has correctly stated, the S/N is often stamped in the rear housing or block, either next to, or underneath the tag. The S/N will read 9UXXXXX, with XXXXX being a four or five digit number that is the consecutive build number of the tractor, as it came off the assembly line.

The S/N may also have "SP" at the end, indicating that "Special Parts" such as optional transmissions, final drive gears, lighting systems, or other specially ordered options, were fitted to the tractor at the factory.
"SP" refers to components that were fitted, in the assembly of the tractor on the assembly line, as compared to other "add-on" options or accessories, that may have been fitted by a Cat dealer, once the tractor left the factory.


[img]http://i50.tinypic.com/2mecgp.jpg[/img]

Ok I was looking at the large tag on the side of the block that is in the middle a few inches up from the oil pan.

So I went and looked at it again and both serial tags have been removed and there is no longer a number stamped into the housing. Oddly enough there is paint on the rivets in both locations. Makes me wonder if someone purchased this cat at a low low price on a midnight sale at some point....

"Large tag a few inches above the pan".....doesn't sound right....that may be a rebuilders tag. Check the normal tag locations for stamped numbers. They are almost always there after you scrape away the paint and crud.

There is one more location to check.....along the engine oil pan flange about under the transfer pump. Picture is of D4 but D6 is similar. Again you will have to scrape and wire brush to find it. Both my 8U & 9U have serial number there.

Thanks I got it. It was still on the flange down there. SU21057

Thanks I got it. It was still on the flange down there. SU21057

Look more closely, the "S" should be a "9". A tag in the middle of the block a few inches above the oil pan usually indicates a power unit or genset engine .. or a military order. This plate will usually have all the engine details on it, including bore and stroke.

I took the "S" as actually being a 9. That seems way to high a serial number to be an industrial or gen set engine number.