Traction Locking front differential?

[Smokeydog]

My M5030DT is built like a tank. Has front autolocking differential. With hilly East Tennessee makes a huge difference.

Hillside mowing, turning uphill and loader operations are greatly enhanced and unnoticed until you try the same with a tractor without it. L3800 and M59 don’t have it. Not sure what tractors have the locking front diff now and didn’t get much help from the dealer. Was hoping the M59 could replace the M5030. The older tractor is a real puller. I know tires make difference.

Grooving the front R4 tires of M59 helped traction.
Maybe I need to quit climbing mountains.

 

[diesel85]

I've always wondered this. They offer, by standard, a locking rear diff.

Why not an option for a front diff lock? Odd...

I could even use this moving snow in slick conditions to turn the tractor from a 3 wheel spinner to a 4 wheel spinner.

 

[Sawyer Rob]

My farm tractor has a manual locking front diff... It was an option...

SR

 

[Smokeydog]

My understanding the M5030 locking differential is a ratcheting type similar to a Detroit locker. It allows either side to over speed the outside tire like in turn to reduce scuffing. Equal power and speed is always available to both wheels. Maybe the only “DT” (double traction) models had this feature? It’s always engaged in four wheel drive. Thought this would be more common on all 4x4 tractors. A regular or open differential like in the rear sends power to the wheel with the least amount of traction.

 

[JWR]

How does that locking front diff feature work? Do you have manual control over it or no ?

I had heard that some newer large tractors (e.g. over 90hp) tend to have limited slip front differentials rather than locking. True ?

 

[Smokeydog]

No manual control for the front axle.

 

[rScotty]

No manual control for the front axle.

We have manual selectable locking front, rear, and center diffs on our cars - Toyota LandCruisers come that way stock. But I've never had any of that on a 4wd tractor. It sounds fascinating.

On the cars, locking the front differential makes steering difficult, How does it work for turning with a load in the FEL? Does the tractor also have a locking center driveshaft differential?

Along with locking axles, the cars also have the option of locking the driveshaft differential between the front and rear axles. That's a total of three different locking differentials, and having the center driveshaft locking option seems pretty important if you are going to lock up both axles at once. But once you lock everything it pretty much only goes in a straight line.

rScotty

 

[Fallon]

My understanding the M5030 locking differential is a ratcheting type similar to a Detroit locker. It allows either side to over speed the outside tire like in turn to reduce scuffing. Equal power and speed is always available to both wheels. Maybe the only “DT” (double traction) models had this feature? It’s always engaged in four wheel drive. Thought this would be more common on all 4x4 tractors. A regular or open differential like in the rear sends power to the wheel with the least amount of traction.

DT is Kubota speak for front wheel assist. Basically 4wd, although technically 4wd refers to machines with equally sized tires.

 

[JWR]

DT is Kubota speak for front wheel assist. Basically 4wd, although technically 4wd refers to machines with equally sized tires.

Strictly a question: Why would 4wd refer technically to machines with equally sized tires? What did you mean there ?

 

[diesel85]

Technically, the only time you lock an axle up is going in a straight line. If not you can risk serious damage.

 

[Fallon]

Strictly a question: Why would 4wd refer technically to machines with equally sized tires? What did you mean there ?

Front wheel assist refers to machines with driven smaller front wheels. 4wd tractors are the big articulating ones with equal sized front & rear wheels. 2wd ones are pretty easily identified & not confused or debated.

Not quite sure why that is & not everybody follows that terminology, but most manufacturers do.

The debate & confusion has been going on for decades... Front wheel assist.....Four wheel ... - Yesterday's Tractors

 

[JWR]

Understand. Not "settled law" but probably most common usage of the terms.

Somewhat similar to cars and SUVs where AWD means all-wheel drive which means you have no control over the feature while 4WD means there is a way to shut it on and off at least and there is some degree of control over the feature.

 

[SDT]

My M5030DT is built like a tank. Has front autolocking differential. With hilly East Tennessee makes a huge difference.
View attachment 590825
Hillside mowing, turning uphill and loader operations are greatly enhanced and unnoticed until you try the same with a tractor without it. L3800 and M59 don稚 have it. Not sure what tractors have the locking front diff now and didn稚 get much help from the dealer. Was hoping the M59 could replace the M5030. The older tractor is a real puller. I know tires make difference.
View attachment 590818
Grooving the front R4 tires of M59 helped traction.
Maybe I need to quit climbing mountains.

Most current Kubota FWA tractors have limited slip front differentials, though some have locking type.

Computer controlled, hydraulically locking front differentials are used on many "deluxe" FWA farm tractors to provide automatic 4 wheel braking on steep surfaces and/or when the brakes are applied.

SDT

 

[Sawyer Rob]

Front wheel assist refers to machines with driven smaller front wheels. 4wd tractors are the big articulating ones with equal sized front & rear wheels. 2wd ones are pretty easily identified & not confused or debated.

Not quite sure why that is & not everybody follows that terminology, but most manufacturers do.

The debate & confusion has been going on for decades... Front wheel assist.....Four wheel ... - Yesterday's Tractors

The only thing I want to add is, front wheel assist refers to the crappy john deer front "hydraulic drive" that deere had for a time. MFWD is the term used for tractors with different size tires on one end.

As I said above, my farm tractor has a "front" diff. lock. It's engaged by pushing a foot petal, just like the rear diff. lock is actuated.

SR

 

[Smokeydog]

No center differential.

 

[JWR]

No center differential.

For sure. I think the various passenger vehicles on paved highways use the center differential to avoid wear, binding and various adverse behavior where there is much less surface slippage compared to farm tractors and where the number of revolutions that might occur while in 4WD is huge compared to tractors. Of course the automotive "AWD" cases have the system in effect all of the time or potentially all of the time so they must have the center differential. The specs on every 4WD (or MFWD) tractor set of tire sizes front vs back are of course predicated on some amount of acceptable slippage between tire and surface in typical operation. None of those are 'perfect' and I think most users would agree that their tractor does not"coast" as easily in 4WD as it does in 2WD, mostly for that imperfect ratio reason.

 

[Tx Jim]

The only thing I want to add is, front wheel assist refers to the crappy john deer front "hydraulic drive" that deere had for a time. MFWD is the term used for tractors with different size tires on one end.

As I said above, my farm tractor has a "front" diff. lock. It's engaged by pushing a foot petal, just like the rear diff. lock is actuated.

SR

JD & other brand tractors with hyd assist FWD were called HFWA or HFWD while the frt wheel assist with a driveshaft to frt axle is known as MFWA or MFWD with M representing mechanical

 

[Smokeydog]

I’m no expert. The M5030DT doesn’t cut the ground in 4wd anymore than the L3800 or M59. It’s not like locking the rear differential. When turning up hill the tractor weight is basically on two wheels. No problem for the M5030. The other two tractors you spin opposite tires of the two axles and have to engage the rear differential lock. Guess I didn’t know how rare this is.
Had a front axle wheel gearcase leak and clicking sound from the front axle. Took it Kubota dealer. Mechanic used the loader to lift the axle off the ground. Rotated one wheel and the other wheel turned the same. “Buddy you got something major wrong”. I explained the locking differential and offered to go back and get the shop manual. They took it apart, replaced all seals and found no damage. Clicking was from low oil. $700 some of the seals are high. Wish my M59 had this feature.

 

[Fallon]

Most current Kubota FWA tractors have limited slip front differentials, though some have locking type.

Computer controlled, hydraulically locking front differentials are used on many "deluxe" FWA farm tractors to provide automatic 4 wheel braking on steep surfaces and/or when the brakes are applied.

SDT

None of the Grand Ls have any locker or limited slip up front. Couldnt say for any of the bigger machines. I believe its reasonably common on the bigger 100+ HP type machines & 4wd articulated monsters of all brands. 20 years ago lots of the big John Deeres had a radar speedometer that calculated wheel slip against a standard speedometer. It gets much more important on the big machines to not wear out tires & maximize fuel economy doing field work all day.

 

[Smokeydog]

Kubota manual calls these a NOSPIN front axle. Are there any newish Kubota tractors in the 40-70hp range with NOSPIN front axle? It gives remarkable improvement in traction. Enhanced loader operation.