Transmission noise

[Marcliff]

Hello all,
I have a 1981 Kubota M7500DT. When I drive the tractor in gear 3 or 4 and it’s under load or going up hill I can hear and feel a clacking/knocking noise coming from what I can tell is from the left side of the transmission. It only happens in gears 3 and 4, In any range. It doesn’t sound like a bearing. I suspect it’s gear lash. Has anyone else had any this kind of trouble? Thanks in advance!

 

[DustyRusty]

Check your gear lube, and if it is low, then replace it. Check the specifications for what weight and GL number you need to use. My guess it will be a 80-90 or 80/90-140 GL4 based on its age.

 

[GeoHorn]

Check your gear lube, and if it is low, then replace it. Check the specifications for what weight and GL number you need to use. My guess it will be a 80-90 or 80/90-140 GL4 based on its age.

I wouldn’t think that. I’d guess UDT,...(got hydraulics...right?). ... but the Owner’s Manual or WSM should specify.

 

[Marcliff]

I wouldn’t think that. I’d guess UDT,...(got hydraulics...right?). ... but the Owner’s Manual or WSM should specify.

What is a UDT? I have the WSM coming in the mail. I’m hoping I can figure this out.

 

[Russell King]

UDT is a Kubota brand fluid that is in the Universal Tractor Fluid family.

I think your manual will recommend 80 or 90 weight gear oil but your dealer will recommend UDT. UDT did not exist when your tractor was built but is a superior fluid for gear transmission tractors that also have a hydraulic pump and system (you have at least the hydraulic 3 point lift).

If your tractor is gear and not hydrostatic transmission then any reasonable universal tractor (hydraulic/transmission) fluid is fine. The UDT is a better fluid but others are suitable from Walmart, tractor supply or dealer.

If it is hydrostatic drive then use UDT, UDT2 or SUDT depending on how much you want to spend.

 

[Marcliff]

That’s for the information but this noise won’t be solved my gear oil. It only makes it in 3/4 gear. It’s a clacking/knocking noise. I think I’ll need to split the tractor and have a look.

 

[rbargeron]

That’s for the information but this noise won’t be solved my gear oil. It only makes it in 3/4 gear. It’s a clacking/knocking noise. I think I’ll need to split the tractor and have a look.

A heavy clicking noise is usually gear teeth partly broken off. it's louder in 3rd and 4th because either the mainshaft or countershaft gear(s) are chipped toward the 3/4 end of the shaft. In gears 1/2 there's lees spreading force on that end. Unless the machine is worked hard in the noisey gears it may run ok for a while and not get worse - the broken pieces are at the bottom of the case and the oil won't pick them up.