2U / 8R? D-8 cats... sliderail gates...

On my 1H D8 the serial number is near the front of the engine below the water pump area.

The 2U series started out with the slide bar transmission and evolved through several transmissions (johnson bar).
Your 2U must be an early one.

I think the slide bar shift was on about the first 1,500 or so 2U's.

Slide bar shifter did not change until s/n 2U5307
Rear s/n plate was inboard, close to the center cover plate, lost from view with any winch attachment.
Shows engine tag behind the pony transmission.

Well, maybe that's not totally correct. I can make out the outline of the #25 CCU mounting adapter in the paint in this picture and the tag would still be visible.

Hi, Smokenrust.
The 2U D8's had the 8R slidebar-style transmission for the first few thousand (Can't remember the change point serial # but someone will have it.) and then changed over to a 5-speed transmission with a forward-reverse lever - which was a LOT more user friendly.

The serial number tag was located on the left side of the back of the steering clutch case about 3 - 4 inches down from the top. Even if the tag has gone walkabout, the # should still be stamped into the housing at that location. If the 'winch' that you mention is a logging winch, that may well cover the tag location but it would still be visible with a DD CCU fitted. If the machine has lost the tag and then been painted a time or two, you may need to do some scraping in that area.

Just my 0.02.

[quote="Deas Plant."]Hi, Smokenrust.
The 2U D8's had the 8R slidebar-style transmission for the first few thousand (Can't remember the change point serial # but someone will have it.) and then changed over to a 5-speed transmission with a forward-reverse lever - which was a LOT more user friendly.[/quote]

The old slide bar was not too bad to run if you work in 2nd gear. 2nd is is straight ahead an Hi reverse is straight back, Lo reverse is one notch over. If you have to go into first it is way over to the left and ahead. If the old bar doesn't slide too good it takes some doing. A little oil helps but attracts dust. It seems like a long way to go when you are on a steep sidehill standing on the brakes to keep from rolling.

Tom

Alright, I am glad I asked the questions...
and for all the answers that I recieved to them.
The 2U, I still could not find the rear tag but some doing I got the engine tag. 2U4851 and has the Cable Control model 9D double drum winch.
I went back out to the old 8R and actually did find the tag on that one... right where Old magnet's 1H picture show it... hid behind the RG LeTourneau Power Control double drum winch assembly... serial number is 8R6747 SP I think... S was not very visible and the p was almost non exsistant... got that off the engine tag. where as after the 8 on the engine tag was nothing till the letter P.
Now just another question, what was the difference between an 8R, 8R-SP and a 2U ? Firewall had the fuel tank for the pup is the most visual on the 8R... LOL
... OK, what were the differences... HP RPMs bore/stroke/ gears, weight, castings ???
Thanks, SnR
[attachment=18827]Cat 8R6747 SP.jpg[/attachment]

Most of the info is covered here...

D8 Information
The 8R series ran out of serial numbers at 8R9999 (Cat only used a maximum of 4 digits in that era, and then went onto a new S/N prefix) .. so the "new" 2U of 1945 was basically the same tractor as the 8R, in 1945 .. it just had a new S/N prefix.

A D8 with the S/N of 2U3351 has a dry main clutch, dry steering clutches and brakes, and is fitted with the 6F, 2R transmission, as in the earlier 1H & 8R series tractors.

At 2U2168, the D8 got heavier steering clutch springs to counter steering clutch slippage, that had been a problem with the 8R series D8.

In addition to the 18% heavier springs, a steering clutch booster spring mechanism was added at the same time to counter the heavier pull pressure required for the steering levers.

The 2U, at its release in 1945, had the same HP as the 8R .. but a power upgrade at 2U3532, in 1947 .. brought power up to 130 DBHP (from 113 DBHP) and 141 FHP (from 131 FHP).
This was achieved by altering the rack setting and increasing engine RPM from 950 to 1000 RPM at this S/N.
This HP increase can be applied to earlier D8 tractors, if they are fitted with both oil-cooled pistons, AND induction-hardened final drive gears.
Oil cooled pistons appeared at D8 tractor S/N 1H6852, and induction-hardened final drive gears appeared at S/N 8R1840.
However, most D8's of the late 1930's and early 1940's would likely have both these improvements fitted by now, as they would have been upgraded at overhaul times, in the 1950's and 1960's.

2U5307 was where a major design change occurred, with the fitment of the new constant mesh transmission that featured 5F and 3R speeds, along with a FWD/REV lever. This transmission featured an oil pump and filter, delivering pressurised and filtered oil to the transmission.