Why turn 4wd off?

[k0ua]

short of starting a new thread, which i was going to do until i discovered this one, the other day i was skidding logs with my hst tractor and got to thinking about 2wd and 4wd. i was using 2wd and everything was going good. i was wondering if pulling heavy (such as skidding logs) with a hydrostat transmission, is it easier on the transmission to be in 4wd, so that there is an extra set of wheels helping to pull and taking strain off the rears, or is it ok to just use 2wd? which do you all think would be easier on the tractor with hydrostat transmission?

I don't see how it would make any difference to the hydro. the load is the load from its point of view. If you were in 2wd and the wheels start to spin, then that would lessen the pulling load on the transmission, But that is apparently not happening as you are maintaining traction in 2wd.

James K0UA

 

[LBrown59]

How can I determine definitively whether the diff on the front wheels locks in 4wd mode? The tractor is a Bobcat CT225, BTW.

Most all tractors lack a front diff lock.

 

[Don87]

.....

 

[Don87]

Some very interesting posts, but sometimes it seems we tend to over think things. I have operated tractors in a way guaranteed by some to cause catastrophic failure yet in over 50 years have yet to break anything in the drive train or blow an engine.

I think you are correct, however your comments makes me think of two things.

1. If we didn't over think things here we would probably end up reading the newspaper more thouroughly with our extra time and that could be really depresssing instead of fun like reading about tractors and stuff.

2. I don't think I would loan you my tractor.:laughing:

Maybe this was meant in jest, but TripleR, Soundguy, K0ua, LBrown, and a few others, I would lend anything I own to.

I know, without a doubt, that they would take care of my equipment, and fix anything that broke while they were using it............whether it was their fault or not.

I am the same way.:thumbsup:

 

[HellBender]

At first, I thought it was like my truck, and the diffs locked when it was in 4wd, so you couldn't use it on pavement. But then I realized it's got a separate diff-lock lever, so that must not be the case. So that leaves me wondering ?

Unless your truck has a custom diff or it came with lockers as an option it's unlikely to have a locking diff. Rear posi at best. Stock trucks are not equipped with locking diffs. But as some one all ready noted when turning the front travels a longer distance than the rears. This causes binding in the drivetrain and something has to give. That's the wheel hop you fell in your truck when turning hard. Greater the traction the less likely the tires will give. I know my SCUT' front tires are over driven to make it easier to turn the front tires. If I have a bucket full bucket my rear tires will give some on a dirt road even though they're loaded. It's not my favorite but stoping is safer.

 

[slowzuki]

Most CUT's that is. Only the Deutz Agrokid has one that I know off. Many larger mfwd's have diff locks like the Kubota M's, most of the MF's, Deutz's, etc. Not sure about JD's.

Most all tractors lack a front diff lock.

 

[joshuabardwell]

Unless your truck has a custom diff or it came with lockers as an option it's unlikely to have a locking diff. Rear posi at best. Stock trucks are not equipped with locking diffs. But as some one all ready noted when turning the front travels a longer distance than the rears.

That's really interesting. I knew that the tires hop when you're in 4wd, and I knew that it was much worse when doing tight turns. I always assumed it was a locked diff between the left/right wheel on the axle. I never thought that the axles didn't have locking diffs and it was just the center diff between the front and rear axles that was locked.

 

[joshuabardwell]

Thanks, everybody. This has been really educational.

 

[Bob77064]

All wheel drive vehicles have a third differential between the front and rear differentials. This allows the vehicle to go turn when the front takes a longer path than the rear.

 

[KubotaEd]

My Kubota B2410 has a feature I don't think was ever put on any other Kubota. As you turn is is designed so the front wheels speed up so they actually pull the front of the tractor around. It is a very nice design, and has never given me any trouble, and I run the tractor in 4WD nearly all the time except when I an on a hard service like blacktop.