g john deere

recently purchased a 1949 jd g noticed it has a large pto shaft I think it would measure 1.5 inches or so .has any one seen this on a old 2 cyl jd. was it an option?

yes, but I think it was on a GM

thanks for the reply.. what was it used for?

Back then pto's were not standardized yet as with the different lifts such as the AC snap coupler, farmall's fast hitch or the john deere 800 & 801 or Yakima hitch. Mainly so if you purchased a certain brand you had to stick with their equipment. Most pto's were 1-3/8 but some were small or larger. I have a JD h and its smaller than 1-3/8. I have a friend with a G and a GM and the GM is larger. Also 540 was not a standard PTO speed either. I'm sure there are other reasons but that's all can put towards this at the moment. Someone correct or shed more light on this subject if I faltered in my information.

I don't think it was a propriatory issue, John Deere thought because the G was a bigger tractor it needed a bigger PTO shaft, 1 3/4 diameter. Adapters are available I believe to 1 3/8 std and I have read on here about guys changing out the PTO shaft for a later one. I don't know when it was they went to std size pto

Here in the south, JD G's that had cotton pickers mounted on them used that shaft. Took more strength to run them without breaking the shaft.
Richard in NW SC

Here's a little more information about PTO standardization -

Way back in 1926 the Farm Equipment Institute (FEI), now called the Association of Equipment Manufacturers (AEM), realized the need to standardize all the various PTO speeds, sizes, and locations that existed. All the various tractor manufacturers had their own favorite designs that all differed and it caused real problems for the independent equipment manufacturers. So they developed what they believed a standard PTO arrangement should be and proposed it to the ASAE (American Society of Agricultural Engineers), which adopted the original standard in 1927.

The standard was titled ASAE S203. It was tweaked somewhat in July 1928, March 1931, and August 1941 to reduce some of the variations in the original standard. That final version resulted in a 540-rpm, 1.38-inch diameter shaft with six splines, located on the tractor’s centerline, and 14 inches ahead of the drawbar pin hole.

The original 1927 Standard called for a speed of 536 +/- 10 RPM. It’s unclear why this exact speed was chosen, but it appeared to be the best compromise between all the various speeds available in those days. For example, a study in 1929 showed pto speeds ranging from 515 to 745 rpm across a range of 35 different tractors.

That standard was in continuous publication by ASAE (now known as ASABE – American Society of Agricultural and Biological Engineers) until early 2011, when it finally discontinued as ASABE decided to adapt a number of ISO (international) standards pertaining to front and rear mounted PTOs.

Apparently Deere didn’t get on the standardization bandwagon until a little later in the game. Field Service Bulletin FSB 148-S, dated June 1944, described a number of “kits” that were designed to retrofit a number of existing (old) tractors to cause them to essentially conform to the requirements of the Standard. The FSB noted that the 1-3/4” diameter shaft of the model “G” was recognized by Standard S203 as an acceptable alternate size.

I don’t know the evolution of all the Deere tractors, but I do know that about that time, the model “H” tractor PTO (“Power Shaft”) was changed from a 1-1/8” diameter shaft to the common 1-3/8” diameter shaft, and there was a change to the drawbar at the same time in order to conform to the ASAE Standard 203.

The option is you have to buy a reducer if you want use it.

Our G had the 1 3/4 shaft too... later Gs had the standard shaft and if you can locate a late parts G, you may be able to swap out the parts.

That's what we did, but it required changing the shaft, the powertrol pump, etc. The end result was much better than the adapter, though!

1-3/8" PTO and Powr-Trol were made standard equipment on JD "G"s @ serial number 43401, about mid-year of the 1950 models. Prior to that, all "G""s from 1937 had the 1-3/4" PTO shaft. Deere made the move as 1-3/8" became the industry standard.
Our 1951 "G" had a JD one row cotton picker as did others in the communIty and as far as I know, the 1-3/8 " size was never an issue.