Rattling/grinding in 3rd

[jsfarmall]

On my 48 cub 1st and 2nd gear works fine, just whining sound which I believe is normal. Gets louder when under a load but no rattling or grinding. 3rd goes into gear just fine with no problem at all but starts with a slight rattle(paired with gear whine) but gets worse the more I drive it in 3rs. It eventually turns into a loud rattle/grinding sound. Dont make much any sense to me.

[Urbish]

Have you drained and re-filled the transmission? I suggest that you remove the transmission cover and have a good look at what is going on in there with a flashlight. Look for broken/pitted/damaged gear teeth. Inspecting gear teeth is much more easily done with the oil drained. Are the shifter forks loose, bent, or cracked? If removing the transmission cover, you'll want to have a new gasket ready or be armed with a tube of form-a-gasket in case the old gasket sticks or tears.

[jsfarmall]

I'm gonna change the fluid this weekend so while it's drained I'll check it out.

[jsfarmall]

I checked under the shifter plate. Shifter fork for 1st and reverse was loose but other than that it all looked good.

[Crimson Tim]

Remember, those forks are reversed in there. The first/reverse fork is the one on the right and the second/third fork is on the left.
Did you tighten up the loose fork, and if so, did it affect your noise?

[Glen]

Hi,
Be sure before tightening the fork bolts that the fork is not rubbing on the clutch shaft, which turns, the guys on here have said that makes noise.

Guess you have already worked on it, if it is making noise, that above is a possible cause.

Here is a pic of the Cub trans under the gearshift cover, this is looking from the left side. The lower fork is the 2nd and 3rd fork.

[jsfarmall]

Yep, according to the picture I tightened the top fork, 1st and reverse. Still didn't help the noise. Stayed the same.

[Urbish]

Did you roll the gears around and look for pitted/broken teeth?

[jsfarmall]

I did but couldn't find anything.

[Urbish]

Might be worth taking off the PTO cover and seeing how the ring gear and pinion are meshing. I discovered a crack in my trans housing and transplanted the guts to a donor housing. The pinion/ring mesh isn't quite right and I have a terrible whine at higher speeds.

[jsfarmall]

I got a whine in all gears and gets worse the harder it pulls.