roger_scotty
Gold Member
In another thread someone asked if all Yanmars have diff locks? I don't know if they all do, but I do know that I've never seen one without it. Has anyone else?
Differential locks?
- Thread starter roger_scotty
- Start date
Roger,
I was the one who asked that question. I think someone responded that they did, however my other question was never answered and that was if they all have in/out 4x4. Meaning that you can run them in 2wd and lever into 4x4 when you need it. Still wondering....
Trent.
I was the one who asked that question. I think someone responded that they did, however my other question was never answered and that was if they all have in/out 4x4. Meaning that you can run them in 2wd and lever into 4x4 when you need it. Still wondering....
Trent.
hosejockey2002
Gold Member
As far as I know, all U.S. and grey market Yanmars in this country have selectable 4WD via a lever. I heard somewhere that newer Yanmars in Japan and elsewhere have full time 4WD with a center differential.
Anonymous Poster
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Guys, that would be my FF205D, to the best of my knowledge. After many emails and much studying of the parts manual I ( and Roger) determined that my FF205D was made to be in AWD or 4wd all the time. It does appear to have a central differential hub. There is no lever on this model. There is a lever shown on the FF205DV model. I have tried to spin the wheels in loose gravel but always one front and one rear wheel will churn gravel. I can post that central differential schematic as soon as my big computer is up and running again. This brings up one question. Does 4wd mean that all 4 wheels pull or is it just one front and one rear wheel pulling?
Bret w
Bret w
Brett,
Well, after thinking about your question about all wheels turning in four wheel drive or only one wheel front and rear, I think if we apply how car diffs work, and consider that all these tractors have a rear diff lock and no front diff lock (except for the tractor with full time 4x4 that you mentioned, I got no clue how that one works), then we can deduce that if you need to lock the rear diff via a lever then it is a "open" normally (the wheel with the least amount of traction gets the most power) and locked (both wheels driving with the same force) when engaged. I think it would be safe to say that the front diff is always open since there is no way to lever it in the locked position. Just a theory on my part, no actual practical experience. I do know that the reason for open diffs on cars and trucks is to allow them to turn without dragging the wheel that is rotating slower than the other during the turn. I think if the front diff was locked always it would be extremely hard to steer without power steering and if all wheels turned at the same rate if both diffs were locked, you would really tear up the ground when turning, that is why they made the rear selectable.
Trent.
Well, after thinking about your question about all wheels turning in four wheel drive or only one wheel front and rear, I think if we apply how car diffs work, and consider that all these tractors have a rear diff lock and no front diff lock (except for the tractor with full time 4x4 that you mentioned, I got no clue how that one works), then we can deduce that if you need to lock the rear diff via a lever then it is a "open" normally (the wheel with the least amount of traction gets the most power) and locked (both wheels driving with the same force) when engaged. I think it would be safe to say that the front diff is always open since there is no way to lever it in the locked position. Just a theory on my part, no actual practical experience. I do know that the reason for open diffs on cars and trucks is to allow them to turn without dragging the wheel that is rotating slower than the other during the turn. I think if the front diff was locked always it would be extremely hard to steer without power steering and if all wheels turned at the same rate if both diffs were locked, you would really tear up the ground when turning, that is why they made the rear selectable.
Trent.
RobS
Super Member
You've nailed it Trent! The diffs in the axles allow each tire to turn at a different speed for turning. Some "full time" 4X4 cars/trucks have a center diff to allow the axles to turn at different speed for turning. On those vehicles, 4X4 really amounts to 4X1. Our tractors don't have center diffs so it's 4X2 without the diff lock. The diff lock brings it up to 4X3, allowing that one front tire in the mud to spin it's little heart out. Diff locks on steering axles do some nasty things (break) if not used carefully. They are available though and lots of rock-climbing jeeps have them /w3tcompact/icons/smile.gif
Anonymous Poster
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If the front axels were locked and live it would be a real pain to stear except in really loose terrain. I have a swiss army Pinzgauer that I can lock the rear at a touch of a lever and lock the font also with a pull of the lever giving me all wheels turning at the same time. On my 2210 yanmar I can push a lever on the floor and lock the rear wheels turning both at the same time. Handy for when you need that extra traction. Most trucks unless you get a diff. locker only spin one wheel in front and back when in 4 wheel drive. They get stuck easier that a true 4x4 and there are not many true 4x4 out there. later, erick