Differential rear lock

[logan97]

when the differential rear is locked can the front be engaged in 4/wd ?

 

[Toolguy]

Yes...

 

[actionaj]

Yes, just don't engage the lock if the rear wheels are spinning.

 

[ovrszd]

The 4wd engagement simply locks the front driveshaft to the same rotational speed as the rear axle pinion assembly.

The Diff Lock simply locks the two rear axle shafts to the same rotational speed.

Neither interferes with the engagement of the other.

Warning, when the Diff Lock is engaged the tractor will not want to turn. With both rear axle shafts locked at the same speed it will only want to go straight. That's why the Diff Lock is spring loaded and requires constant input from the operator to stay locked which is a safety procedure to help prevent the turning problem.

I frequently use the 4wd and Diff Lock at the same time. Provides you with true 3wd drive. True 4wd can only be achieved if your front differential has a locking device. I don't know of any tractors that do.

 

[gwdixon]

I frequently use the 4wd and Diff Lock at the same time. Provides you with true 3wd drive. True 4wd can only be achieved if your front differential has a locking device. I don't know of any tractors that do.

The M7040, M8540, and M9540 all have an automatic front locking differential (limited slip). It was one motivation for purchasing the M7040 recently.

I have been in true 4WD only on a couple of occasions but it works just like you might imagine. Four R1s gripping the ground with 70HP is impressive. It is not like a big ag tractor but is plenty enough to do anything on a small plot.

 

[20 20]

yes it can, just remember to disengage before turning on hard surfaces

 

[ovrszd]

The M7040, M8540, and M9540 all have an automatic front locking differential (limited slip). It was one motivation for purchasing the M7040 recently.

I have been in true 4WD only on a couple of occasions but it works just like you might imagine. Four R1s gripping the ground with 70HP is impressive. It is not like a big ag tractor but is plenty enough to do anything on a small plot.

I didn't know that gw, thanks for the info.

I'm a Jeep freak and frequently use a mechanical locker in the front axle. The multiplication effect of that added traction is amazing. Must be used wisely as you can bust front axle components by a simple blip of the throttle!!!

 

[bstrom]

Yes, just don't engage the lock if the rear wheels are spinning.

Huh, I thought that it was ok to do that - at a reasonable speed - so that it engages easier and you then gain traction. I'm wrong on that?

 

[DavidAubke]

Yes, just don't engage the lock if the rear wheels are spinning.

I also thought this was OK - within reason. The only way I can get things to align properly for the lock to engage is to let the slipping wheel spin slowly while putting a little pressure on the locking pedal. I wouldn't just jam it down while the wheels are spinning quickly but otherwise...

 

[BotaBX24er]

I also thought this was OK - within reason. The only way I can get things to align properly for the lock to engage is to let the slipping wheel spin slowly while putting a little pressure on the locking pedal. I wouldn't just jam it down while the wheels are spinning quickly but otherwise...

wuh oh ...how can I tell if I did any damage to it by doing just that.

 

[Matt_Jr]

The wheels MUST spin a little or the locking mechanism won't align. The alignment of the mechanism occurs when one tire spins faster than the other. You just don't want it to spin fast enough to grind. If it's grinding.. well.. that's bad.

 

[DickS]

Or, if you can anticipate the use of the rear lock and are not stuck yet, turning the steering wheel either way while moving will cause one wheel to rotate faster than the other. Light pressure on the lever will allow the wheels lock easily.

 

[jnjpream]

Maybe actionaj was referring to engaging the 4wd while the tractor is standing still but the rear wheels are spinning..

It can start an annoying grinding sound that leads up to a clunk followed by sudden forward movement. At least that's how it works on my old pickup.

 

[taborekle]

Yes, just don't engage the lock if the rear wheels are spinning.

I've done this several times and haven't seen any adverse problems. I'm in 4wd and am tillering a field. The tractor slows as it hits some soft ground and the rear wheels start to slip more then usual. I depress the diff lock and the tactor seems to grab and I get through the soft soil and then I get off the diff lock and continue.

Perhaps I'm doing something wrong? To me, this seems very normal.

 

[bstrom]

Here's what the b series (B2x20) manual says:

+When using the differential lock, always slow the engine down.

+To prevent damage to the power train, do not engage diff lock when one wheel is spinning and the other is completely stopped.

+If the diff lock cannot be released in the above manner, step lightly on the brake pedals alternately.


I never slow down the engine and have never tried the brake thing. I just let off the HST pedal some I think, then step on the diff lock. I don't really know if one wheel is completely stopped but so far I haven't heard any grinding.