2019 Massimo T-Boss 410 How To Unlock Differential

[Locking Diff]

I just purchased a new 2019 Massimo T-Boss 410 March 2020. I haven't figured out how to unlock the differential?  There isn't a switch?

[T-boss 410]

I asked the same question to a Massimo tech. He advised that the differential only locks when the 4 wheel drive is engaged. 

Hope this helps!

[Locking Diff]

Thanks, I'll see if it is still locked.

[T-boss 410]

So, what was the verdict?

[Locking Diff]

It's been nasty weather and I haven't had it out. So I don't know if it's still locked or not? Thanks, I'll let you know in a few days.

[T-boss 410]

OK, thanks!

[Locking Diff]

Just got off of the phone with guy from the factory and he said that it's always locked. That just can't be right. The big boss wasn't there today but I have his Ph# 972-893-3180 his name is David Stontz?. I'll try to call him tomorrow and let you know what he says.

[T-boss 410]

Are we talking about the front or rear differential? The front diff is the one that locks when the 4X4 is engaged. At least, that's what the tech said. I don't know about the rear diff. I have downloaded both the owner's manual and the parts manual, but I don't remember seeing anything about the rear diff. 

[T-boss 410]

Did you ever get in touch with the big boss? Just curious about the answer, since I have a T-boss, also. 

[Locking Diff]

  They have told me that the rear differential is always locked and it's the front one that locks when put in 4wd. It sure makes it hard to turn on wet grass, gravel or concrete.  Not a good design, you have to give plenty of gas to get it to go while turning  going slow. Other than that it seems like a well constructed unit,, it does what I need. It could use power point to plug in my sprayer.

[T-boss 410]

So, unlike a limited slip differential such as in the automotive industry,  it's locked always? Yeah, I can see how that would make it more difficult to turn. You would think the engineers would have taken that into consideration during the design phase. I have used mine for some yard work, and I can see what you mean. It doesn't have a very tight turning radius. Great for straight line traction, though. 

[Dan B]

I'm running the risk of telling you stuff you already know.  Your Massimo (made by Hisun) and the Bennche have similar 4WD/Lock systems.  In 2WD, the rear diff can't be locked (shouldn't be unless there's a problem with the actuator).  You can select 2WD or 4WD unlocked differentials.  There's a lever that covers your lock/unlock select switch.  You rotate if you're in 4WD to uncover the lock/unlock selector.  This switch locks both front and rear differentials; not independently selectable.  Apparently, you can't lock just the rear diff or just the front diff.  If you can, jack up the rear of your machine and select 2WD, neutral transmission.  Turn one of the rear wheels; the other wheel should rotate in the opposite direction if unlocked; same direction if locked.

It doesn't make sense to have a differential locked when driving on hard surfaces.  Puts too much stress on the internal differential parts and tires.

[Rocket]

Here is the dirt on the Massimo T boss 410 UTV side by side differential. It doesn't have one in either the front or rear. It’s simply a ring and pinon gear set. Therefor it can not be unlocked. It’s always, permanently locked! I asked Massimo if there is a locking differential option for this model, NO. Is there an after market locking differential available for the 410 side by side? So far google has not found one.

[Joe Breaux]

On 4/10/2020 at 9:23 PM, Dan B said:

I'm running the risk of telling you stuff you already know.  Your Massimo (made by Hisun) and the Bennche have similar 4WD/Lock systems.  In 2WD, the rear diff can't be locked (shouldn't be unless there's a problem with the actuator).  You can select 2WD or 4WD unlocked differentials.  There's a lever that covers your lock/unlock select switch.  You rotate if you're in 4WD to uncover the lock/unlock selector.  This switch locks both front and rear differentials; not independently selectable.  Apparently, you can't lock just the rear diff or just the front diff.  If you can, jack up the rear of your machine and select 2WD, neutral transmission.  Turn one of the rear wheels; the other wheel should rotate in the opposite direction if unlocked; same direction if locked.

It doesn't make sense to have a differential locked when driving on hard surfaces.  Puts too much stress on the internal differential parts and tires.

My MSU 500 is the same.. rear is not locked under 2wd position and front axles free wheel . you select 4wd, then slide cover and press LOCK .. it is much harder to steer in lock position .. warning sticker  next to selector .. DO NOT EXCEDE 18 MPH in LOCKED position.. 

[Mackc]

About whether there is a "locking differential" on their UTV??????   There is so much misinformation appearing here from folks that don't have any idea what they are posting, check it out for yourself rather than jumping on the smart phone or computer and asking questions.

[dmit]

very few atv's or utv's have an unlockable rear differential, in fact the majority have no rear differential, the few that do actively promote them as having "turf mode".

atv's and utv's are not designed to be driven on hard surfaces

[Mackc]

On 3/20/2020 at 9:27 PM, T-boss 410 said:

Are we talking about the front or rear differential? The front diff is the one that locks when the 4X4 is engaged. At least, that's what the tech said. I don't know about the rear diff. I have downloaded both the owner's manual and the parts manual, but I don't remember seeing anything about the rear diff. 

Sorry to disappoint you about the rear "differential" There is NO DIFFERENTIAL in the rear! The rear end is just a ring gear and pinion, If you doubt what I am saying jack up both rear wheels and with the shifter in neutral and the parking brake off, spin one wheel, if the opposite wheel turns the same direction as the one you are spinning there is no differential when you turn,  the wheels slide around the corner, both at the same speed

[Joe Breaux]

so ,only the front axles lock and unlock ?...... then why does my MSU 500 have controls to engage 2wd or 4wd and then seperate control to engage 4wd LOCK along with indictors on dash to show whats engaged ?  just fake? 

[T-boss 410]

3 hours ago, Mackc said:

Sorry to disappoint you about the rear "differential" There is NO DIFFERENTIAL in the rear! The rear end is just a ring gear and pinion, If you doubt what I am saying jack up both rear wheels and with the shifter in neutral and the parking brake off, spin one wheel, if the opposite wheel turns the same direction as the one you are spinning there is no differential when you turn,  the wheels slide around the corner, both at the same speed

Hey, I'm just passing along some information I got from a Massimo tech. 

[Mackc]

Massimo Tech? could that be an oxymoron term for a person that bolts wheels onto a Chinese crate job?

[Mackc]

On 1/24/2021 at 11:56 AM, Joe Breaux said:

so ,only the front axles lock and unlock ?...... then why does my MSU 500 have controls to engage 2wd or 4wd and then seperate control to engage 4wd LOCK along with indictors on dash to show whats engaged ?  just fake? 

From what I am seeing the 4 wd switch engages and disengages the front wheel drive, and maybe it don't work when the transmission is in REVERSE?

[T-boss 410]

Well whatever. He's been helpful with some questions I've had, and he answers my emails. He's even sent me a portion of his service manual (electric section). I can't fault the guy. 

[Joe Breaux]

4 hours ago, Mackc said:

Massimo Tech? could that be an oxymoron term for a person that bolts wheels onto a Chinese crate job?

lol   yeah, massimo tech = tractor supply employee 

[Joe Breaux]

4 hours ago, Mackc said:

From what I am seeing the 4 wd switch engages and disengages the front wheel drive, and maybe it don't work when the transmission is in REVERSE?

most things on it dont work in FORWARD  ..lol

[Dan B]

On 1/24/2021 at 10:56 AM, Joe Breaux said:

so ,only the front axles lock and unlock ?...... then why does my MSU 500 have controls to engage 2wd or 4wd and then seperate control to engage 4wd LOCK along with indictors on dash to show whats engaged ?  just fake? 

Why do they do that?  Bad design, cheap, saves money.  Since the rear axle is always locked, then the front axles can be locked only in 4wd.  If not in 4wd, no sense inlocking a diff that has to drive power going to the axle.  My ride has independently lockable front and rear axles along with independent 4wd selection.

[Joe Breaux]

no question that Massimo is cheap ,poorly designed and saves them money... not honoring any warranty claims also saves them millions .... I wish somene had told me BEFORE I trusted Tractor Supply and bought one from them ..... 

[Travis]

7 hours ago, Joe Breaux said:

no question that Massimo is cheap ,poorly designed and saves them money... not honoring any warranty claims also saves them millions .... I wish somene had told me BEFORE I trusted Tractor Supply and bought one from them ..... 

Never take the word of the salesperson  

[cliffyk]

On 1/24/2021 at 1:37 PM, T-boss 410 said:

Hey, I'm just passing along some information I got from a Massimo tech. 

THe Massimo tech was wrong, the vehicle has a final drive gear case, which they incorrectly refer to as the "Rear Differential" in some parts lists I've seen--such as shown below:

However if you study the exploded parts diagram you will see that both axle shafts insert directly into the ring gear hub--there are no side gears, no carrier or spider gears--I.e. no differential. They can call it one but that does no make it one just as calling a cow's tail a leg does not mean a cow has five legs.

My Coleman Outfitter 400 (Hisun HS400) is the same. When I first got it I was surprised by how capable it was in 2WD, then I saw the part disgram and realized it had. in effect,  a full-time "locked" rear end--that explained it...

The front final drive however does have a differential. It is shown in pars lists as an assembly--however it has the distinct shape of an integral ring gear/carrier assembly:

 

Part #19 above is a sliding splined coupler that in one position locks the differential...

[T-boss 410]

OK, then it's a spool.

[cliffyk]

5 minutes ago, T-boss 410 said:

OK, then it's a spool.

Yup... 

The rear track is so narrow there's no real need for a differential--the front OTH has to deal with steering as has been mentioned here, drive it on a hard surface with the differential locked up and the need for same becomes quite apparent.

I agree that the Hisun and other lesser cost Asian ATVs and UTVS are not for those with little to no mechanical knowledge--knew that going in--those who must run to the dealer to have the spark plug and oil changed should not buy one..However,parts for my HS400 seem readily available and the machine itself is remarkable in its simplicity..

What I've seen so far is well-engineered and fabricated, the castings are sturdy and nicely machined (I was surprised tp see forged steel spindles front and rear), and the welds are near perfect.  It has grease fittings everywhere you'd want one and given the overall package size maintenance thingys are quite accessible.

I have no complaints and see no reason why it will not provide a good and long service life. IF I keep it clean and lubricated as required--and do not beat-the-shit out of it as is far too common with this sort of vehicle.  Time will of course be the final arbiter.

My stepson went through a $16000 Yamaha Jet-Ski in less than 9 months--did not follow break-in procedures; or perform early maintenance; and beat the piss out of it every chance he got. He rolled it and sunk it a couple times and didn't even change the oil. 

Unfortunately this is the norm for a lot of motorized recreational toys...