I picked up a new toy to add to the Caterpillar stable. Amazingly this one was just across town from me. It's a 1936 Caterpillar Gas 50. The serial number is 5A1145SP. Can someone please see if the serial number is a '36? Does anybody know what the "SP" stands for?

I got the tractor from the grandson of the owner. It was passed for son to son to son, then me. One of it's many jobs along it's life was building I-640 around Knoxville, TN.








With the blade removed, it's ready to haul:




Using the D2 to see how stuck the tracks are:



I was pleasantly surprised to find the clutches and brakes free and operational.



Getting a little assistance loading it up:




Changing a trailer tire that went flat due to a bent rim. Tree stumps are hard on rims.




Safely relocated in line for restoration.




The tractor is undergoing an expert inspection:

wow is that in very very nice shape, like the way you loaded and hauled it.

the helper will be a big help on restoration, keep us posted

thansk

My book shows it as a 1935, SP stands for special parts as an indicator for the assembly that it was other than a standard tractor. It could have been the belly pan, guards, gearing etc.

That looks like a nice straight FIFTY for a project tractor. The manifolds look pretty nice and the u/c looks like it has life left.

Here’s what Caterpillar had to say about the letters SP for that date of equipment.

SP= Special parts

“SP” stamped at the end of the Serial Number indicates special parts were substituted for standard parts on the machine. Examples include special transmission gears, oversized idlers in place of standard idlers, and other items that required special attention on the assembly line, usually “deep” in the machine. “SP” was not used for add-on accessories such as lights, cab, PTOs, crankcase guards, and mufflers.

Although these markings do not indicate the type of special gears, if any, but they do afford an opportunity to check the original gears installed in the machine to insure against replacement with standard gears.

There were later changes in the transmission and final drives as to special parts, but they would not concern your tractor. I forgot...nice find.

Kelly

Hello Ktmrider,

What a GREAT find in your immaculate condition for it's age gas "50", a real find these days. You ask what year your GEM was built, well tractor Serial No 5A 1145SP was built during the 1935 production year at Peoria. It is one of a total of 1808 tractors built from commencement in 1931 until it was discontinued in 1937.

Hope that this data is of interest to you.

Sincere regards

Alan T.Lewis
Christchurch
NEW ZEALAND

Great pictures of the recovery

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Good looking tractor

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and it looks like to me that the "helper" has already taken a supervisory postition with the operation.

Really adds to the story to know where some of this old machinery spent its time----shame old tractors can't talk

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they would all have an interesting story to tell.

Good luck----

Delta Dirt

Great find:D great history....and condition to.
Is that a LaPlante Choate Blade???
I also especially like the picture of "junior" in the seat"
If ya listen real close, I believe he's got the engine sound going already....
Thanks for sharing the recovery.

Nice find and a bit of history makes it even better. The 50 appears to be very intact and pretty darn straight. Free frictions, wow that's kind of shocking. Congratulations and thank for sharing your new project. Don

"Old wrote:

Is that a LaPlante Choate Blade???

It sure is.

Thanks for all the kind comments.

Well, I just bought the Cat pictured in this thread and it will be comming home to SC !
I also bought another Gas 50 on the same day about an hour & a half away, but that one looks much worse for wear. I would like to see how many gas 50's are still out there, and what the parts situation might be. What Cats share the same undercarrage please! Those finned manifolds sure look cool, but they catch hell from the rust & heat. Both tractors could use a pretty set. Would anyone else be interested in having them recast?. I would also like to see some pics of original tractors both to judge how much work I need to do and to inspire me toward the restoration effort. Thanks!