Whining PTO? Rear Differential?

[Travis_R]

'98 MF 231 is now making a noticable "whining noise". I can really tell when the PTO is engaged and the rear tires are rolling. PTO is set around 2,000 engine RPMs.

It hasn't gave me a bit of trouble and the tractor has a little under 970 hours on it. Goes in and out of gear just fine. Would changing the trans./hydraulic oil make it run quieter? The oil does smell a little burnt to me. It probably had never been changed. I've had it for 4 years and bought it with 480 hours on it.

Should there be a concern and have a mechanic come look at it or just keep on using it?

I don't think it's the gearbox on the Bush Hog making the noise.

Are there any tests or tricks that I can perform myself to maybe see what's going on?

Thanks!

 

[Travis_R]

Well without the bush hog (rotary cutter) hooked up, I'm not hearing any whining noise with the PTO engaged and the tractor is rolling.

So now I'm thinking it's the gearbox on the bush hog making the sound??