John Deere 420 Info
John Deere 420 Info
I am new to crawlers and have little knowledge about them. Are there any books or manuals that can help me? I have a parts manual that has come in very handy so far.
- Stan Disbrow
- 350 crawler
- Posts: 2898
- Joined: Fri Jul 15, 2005 3:13 pm
- Location: Raleigh, NC
Hi,
Are you fairly knowledgeable about wheel tractors in general? If so, that'll make it easier to understand crawlers.
The major differences, you can see (i.e. tracks instead of wheels, track frame, track rollers, etc). From the engine through the transmission, things are pretty much the same as on the wheel tractors.
What you can't see is inside the final drive housings, which is where the service manual comes in handy. Lots of nice photos in a service manual showing you all the bits.
The basic difference is there is no differential, and there's a set of clutches for each side of the machine. There is still a ring and pinion gear, but there are no spyder gears. It's locked solid.
When you pull back on the steering lever, it operates a drive clutch inside the final drive housing. That disconnects power to that track. Then, as you pull back further, a band brake is applied, stopping the track on that side. The opposite track is still powered, so it literally drives around the stopped one, turning the machine.
So, the major differences between a tractor and a crawler are mostly in the final drives and track assemblies.
Now, if you are new to tractors in general, there's a lot more to cover. In either case a JD service manual will be a great help to you.
Stan
Are you fairly knowledgeable about wheel tractors in general? If so, that'll make it easier to understand crawlers.
The major differences, you can see (i.e. tracks instead of wheels, track frame, track rollers, etc). From the engine through the transmission, things are pretty much the same as on the wheel tractors.
What you can't see is inside the final drive housings, which is where the service manual comes in handy. Lots of nice photos in a service manual showing you all the bits.
The basic difference is there is no differential, and there's a set of clutches for each side of the machine. There is still a ring and pinion gear, but there are no spyder gears. It's locked solid.
When you pull back on the steering lever, it operates a drive clutch inside the final drive housing. That disconnects power to that track. Then, as you pull back further, a band brake is applied, stopping the track on that side. The opposite track is still powered, so it literally drives around the stopped one, turning the machine.
So, the major differences between a tractor and a crawler are mostly in the final drives and track assemblies.
Now, if you are new to tractors in general, there's a lot more to cover. In either case a JD service manual will be a great help to you.
Stan
There's No Such Thing As A Cheap Crawler!
Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)
Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)
- Stan Disbrow
- 350 crawler
- Posts: 2898
- Joined: Fri Jul 15, 2005 3:13 pm
- Location: Raleigh, NC
Hi,
Kewl! You're halfway there with the parts manual. Those diagrams are quite useful. The service manual is loaded with instructions on how to get things apart, and more importantly, back together again! :p
Once you have both manuals, you'll be fairly well off. After that, it's a matter of finding parts, and that's where Lavoy comes in. I think he has enough parts to go into crawler production.
Stan
Kewl! You're halfway there with the parts manual. Those diagrams are quite useful. The service manual is loaded with instructions on how to get things apart, and more importantly, back together again! :p
Once you have both manuals, you'll be fairly well off. After that, it's a matter of finding parts, and that's where Lavoy comes in. I think he has enough parts to go into crawler production.
Stan
There's No Such Thing As A Cheap Crawler!
Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)
Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)
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