3-Point Hitch Mitsubishi MT372 Keeps snapping shear pin

[annegil3]

Every time I put in a new pin then use the grader box or tiller, it snaps again. Never owned a tractor before but I have had official tractor repairman replace two of them as well with the same result!

 

[CalG]

We can't be sure which pins are failing based on your description

A "grader box" doesn't take a PTO on first impression but a tiller does.

Just what is shear pin is failing? The usual reason shear pins fail is because the load is to large!

 

[Baby Grand]

Every time I put in a new pin then use the grader box or tiller, it snaps again. Never owned a tractor before but I have had official tractor repairman replace two of them as well with the same result!

Welcome to TBN, annegil3!
I'd like to clarify which pin is shearing so the gang can get you back to using your tractor productively.
Is this a shear pin in the rotating PTO shaft assembly, or is this a pin in your implement's hitch?
Maybe between the lift arms
The reason I ask is that I don't use any shear pins
If you can post a picture of the pin, or refer to the picture, here, that would be very helpful.

 

[Maxify55]

Welcome, as well, from another MT372 owner.
I've had to learn from the bottom up with this unit. I'd only ever used CUT's and yard tractors.
So a sub-compact was another special treat in learning hydraulics and gearing.
I run a 48" Sitrex finish mower and a 48" ETA rotary cutter off the PTO with no problems.
AFTER I solved the counter weight issues, this is.
You didn't notice a "D" on the end of tractor, right?
It's not a 4WD unit with a great big drive axle out front for extra weight.

Anyway, to your issue and the sheer pins.
My guess is that you're throwing too many rpm's at the attachment.
Did you know that you have a tractor with a multi-speed PTO transmission?
Tractors built for the US market today have a single speed PTO geared to 540 RPMs.
Yours, if it's like mine, has a shifter to vary the speed to your attachment drive shaft.

Use only the #1 gear when operating your equipment.
Any other speed is far too fast for the equipment to handle.
For 15 HP at the crank and 12 PTO ponies, it can and will snap a sheer pin.

Hope I helped your situation.
I'm just dumbfounded at the amount of work my little tractor can perform
and in Florida heat, too, is just amazing.

I have to whisper around my LS, though.
Don't want any hurt feelings.
They're stable mates. :laughing:

 

[Maxify55]

I just thouight that maybe you'd gotten your MT without the stickers showing you the gearing positions.
What a Dolt!

My apologies:
View attachment 430431

It's an '85 model and still working it's heart out.

 

[Maxify55]

I just thouight that maybe you'd gotten your MT without the stickers showing you the gearing positions.
What a Dolt!

My apologies:
View attachment 430431

It's an '85 model and still working it's heart out.

The pic won't load for some reason.
One more attempt before I give up.



I can find more ways to own the names to which I earn the names I call myself.

"Dolt" is one of the nicer, more repeatable ones

 

[annegil3]

The pic won't load for some reason.
One more attempt before I give up.

View attachment 430623

I can find more ways to own the names to which I earn the names I call myself.

"Dolt" is one of the nicer, more repeatable ones

Have been unable to catch hubby long enough for him to respond to your wonderful suggestions due to family catastrophes and long work hours, but this certainly sounds like the answer to our problem. He did tell me its in the gearbox where the pin shears and that's as far as we got. We did know it was a 2WD and that the cutter we had on it was indeed too big. But the box and tiller should cause it no problem. But when I get him out there to mess with it again we will indeed check to make sure it's in 1st gear and try another lift, once he finds another pin to replace the broken one with. I don't believe it has the numbering on it and I couldn't enlarge the photo enough to see the numbers. I would assume, the further away from your body you push it is number 1? Love how informative you have all been. Yes dolt is a nice name, Homer!

 

[Maxify55]

Yep, push the shifter all the way down/forward. The other shear pin he maybe referring to might be the differential locking pin.
It's a very very small pin deep within the rear gearing that will sheer if depressed too quickly or with too much force.
use it gingerly and engage it while the machine is stopped and even after engaging, be very limited in it's use.
However, it IS a life saver for a 2WD tractor when in difficult traction situations.

Cheers to You and Yours