1940 M

Hello, I just picked up a 1940 M and i have noticed that it has parts that are different. The top deck is not slotted but has the shifting pattern through 4th gear, no 5th indicated(I know that 5th is there). Tractor has an 11,000 serial number and most casting codes are J. The engine is a 248 block but has a B casting code and the serial number is not stamped into the pad above the dist. I bought the tractor as parts and did not really intend to fix it up but the tranny cover has me intrigued so I thought that I would try to see what every one else thought about it. Thanks, Mike

M's and H's that came on steel had a lockout bolt to block out 5th gear becasue it was too fast. I would assume they used the same covers but maybe not. I'm probobly wrong but I figured I'd take a swing at it.

1939 and early 1940 M used the slotted transmission top cover. Don't know the serial # break. I have SN 11576 which has been in the family since new, it has the flat top cover but no raised markings for the shift pattern. Came on rubber. Also had the engine block replaced because it froze up. Has no SN on block. Was told by someone on Red Power that replacement blocks did not have serial #s but replacement engines did.

serial # 9286 was the last with slot top. Does the engine have a cast # 365586 R1, or is it ground off, or ground off and a # stamped in? Does it have a cover plate on side of block near carburetor with 2 bolts holding plate to block? Maybe a dipstick or dipstick hole pluged versus never drilled? If block actually has C-248 cast on block, that and all above could indicate a replacement block.

Hey Dave,

Went out and checked my M block. I knew it had the two bolt cover below the carb for a fuel pump I presume. It also has the dipstick hole plugged with a welch plug. The casting date code is M and the rest of the tractor is J. The "casting #" is 6943 DB . The "DB" is cast but the "6943" is stamped where a previous # was ground off. Can you enlighten me anymore about the meaning of this? Thanks.

6943 # is for a replacement block for early tractors before the R suffix numbers came along. your block was probably cast in 1942. Wish I could tell you why the numbers are ground off sometime, must have been different numbers than what they wanted on block, but don't know. Sometimes find them ground of with no numbers stamped back. I suspect the other poster has a block cast in 1956 which brings up another mystery. The cast # 365586 R1 replacement blocks can be found with any of the following, C-248, C-264 or C-281 cast on side of block, even though the cast # of block is the same. Hope this helps.

The top cover does not have the slot, but what I was trying to say was that it has the shifting pattern through 4th gear cast into it, not showing 5th gear. I was curiose as I had never seen a M with the raised cast shift pattern. I will get the casting numbers off of the block this evening, I was only really looking at casting codes when I looked earlier. Thanks for the info so far, Mike S.

Mike,
If you don't mind, please post your serial #. I would like to know how far apart we are. Thanks.

Thanks for the info.

No C-248 on my block that I can find. Did notice one other oddity I think. Below #2 spark plug and in back of the serial # pad is a machined surface about 2 inches long by 1 inch high with two round headed screws in it. Any ideas on this one?

Some updated info on the '40 M. Tractor serial number is 11472, block casting number is ground off and stamped 6943-DJ with a casting date of 1-16-B. Head casting number is 8574 DC. Block has a plate covering the fuel pump opening and a soft plug in the dipstick hole. Also the timing cover has a part number that ends with R2 and is machined for the hour meter. I am guessing that this is a newer replacement engine? Good news is that I pulled the plugs and it turns over fine and I can see the firecrater pistons. Thanks for the help

Hey Mike,
Thanks for the S/N.

Afraid I don't have the answer, when looking at parts close there's lot of little things that show up different sometimes. On Mikes block the stamped in # 6943 and the DJ suffix was the last 4 digit number used for a replacement. I suspect his block was a 6 digit with the B code before it was ground off. The 8574 DC head mike has with DC suffix was not made until after M tractors were out of production.

Zach B. is probably onto something. The tractors sold on steel had the 5th "gear" locked out by a long bolt that simply kept the shift rail from moving forward when the shift lever was pulled back toward fifth. Here is a quote from an early sales brochures (maybe 1940 or 1941): "Four ideal working speeds, with manual governor control, provide perfect adjustment of speed--a perfect gait for every field job. The fifth, or high speed built into the rubber-tired tractors is a real time and labor saver on the road." Sounds like the transmissions are built differently, but they are not. If a steel-wheeled tractor was converted to rubber, it took about 2 minutes to turn the locking bolt out enough to let the shift rail move forward. I don't know whether people put a lock nut on top or not. Probably most people and dealers would just get a shorter bolt from the hardware store so they could run it down tight into the transmission cover.
I've often wondered if an H on steel would even have enough power to move the tractor in fifth. It would be some ride if you gave it enough gas so that it would move (the specs call for 9-1/2 to 15-5/8 mph in fifth, which suggests that the engine has to be revved up part way to get enough power to pull anything). I remember the Hs we used that would pull almost nothing in fifth at the speeds you could use with a steel-tired wagon on a washboard gravel road. The engine was running so slowly at 5 or 6 mph that there wasn't enough torque. You had to resort to fourth wide open (noisy!) to get between 5 and 6 mph.
I used a couple of steel-wheeled tractors for at least 10 years, and I remember VERY WELL the bone-shaking ride on hard ground or roads if you went even 3 mph. I would usually go on the road in second gear, throttled back. Otherwise, the tractor did a St. Vitus dance and you HAD to stand up. Steel wheels waste a lot of power, and apparently more power the faster you go. Our 10-20 would do NO heavy work in third (about 4.25 mph)--no plowing, no disking--but it would work through anything in second (the old "plowing gear," which I think engineers calculated to give enough power to pull the "rated load" of a certain number of plows; most tractors of the 30s and 40s seem to have had a "plowing gear" around 3 mph).