420 transmission case

[gus]

My tractor has a cracked case (I bought it knowing that). The case has been ground and welded. Ground right through the casting number.

The only thing I can read is the first letter, M3. The junk yard has a case but I don't have their casting number yet.

My tractor is a first year, 91,000 serial number. How interchangeable are the cases? They said they can get one, but I would pay freight. If the one they have will work, no freight.

Second question: Are the transmission gears the same in a 40 wheel tractor as a 40C?? Both 4 speed tranny's
gus

[JimAnderson]

Gus,
Don't have a 40 parts manual so what I say is based on the 420/430
series.The crawler and wheeled tractors used the same internal transmission parts if they fell into the same serial number breaks.
As long as the speed count was the same no problem.
The differences are in the cases and pto shafts.I would guess that
the internals for the 40 series would follow the same logic.
I look for wheeled tractor transmissions because they rarely got
shuttle shifted like a crawler does and the gears generally look
better.Hope this helps.JimAnderson

[gus]

I have a complete 40 wheel tractor transmission and the junk yard will give me $100 trade in for the case I need (case only for my 420). I was hoping the case would work, but it does not.

I'm debating the trade in. I also have a 40C and if I needed gears later on, I would probably pay more than that. I need to find out if the gears would also work in the 420C. If they do, I would keep them for sure.

If things work out, I will put the 40 back together and sell it. There is a nother 420C with the JD heavy loader for sale that I would like to get. I would then have 2 420's, one with loader and the other with a blade.
Gus

[Lavoy]

A few of the gears are different between tractors and crawlers, learned that one the hard way many years ago. I installed a complete input shaft from a tractor in a crawler, and all the gears bound up.
I have transmission cases on hand if you need one.
Lavoy

[Stan Disbrow]

Hi,

Oooh. I bet that caused a few choice words to pop out! You find that out by trying the gears with the case still on the bench or did you wait until after the machine was reassembled?

Stan

[Lavoy]

Lucked out, it was so tight that I could not even install the input shaft bearing holder, so caught it right away. As to choice words, every construction worker in 5 miles was blushing.
Lavoy