M rearend noise

sorry if this get's too long. main bearing on pilot shaft went out gathered all the bearings and replaced all of them. luckily we were able to get all the rollers out before any went through the case. this m always had a little gear noise but after we replaced everything and put in new 80/90 oil it is very loud. the main pilot bearing we got from our local ih dealer was not a roller bearing like the original. it was two rows of ball bearings and we were told that we couldnt use the bolt that goes on the end of the shaft. just looking for any ideas thoughts as to why so much noise? thanks for any help.

The wear pattern of the differential pinion to ring gear was probably worn in over many years of the eventual failure of the intermediate bearing you replaced. A new bearing will likely change the angle of the pinion to some degree or another, possibly making much more noise. (assumes the other bearings are in good shape) Jim

yes all the bearings got replaced since we had to get in there anyhow. so you think that the noise is just the gears lined up a little more where they're supposed to be?

i forgot another piece of info. when you push the clutch in the noise almost goes away. but when you let out there it goes again. its noisey nomatter what gear you're in. and neutral.

It is beginning to seem to me to be a bearing or drive coupling issue. The new bearing needs to be held in place (my opinion) is the shaft is worn where the bearing is now located, the new bearing might be allowing the shafts to be improperly aligned and noisy. If the noise happens while the tractor is stopped in neutral, the issue is not the pinion and ring, these are not moving. If it is present when the tractor is in fifth the bearing is not used, therefore it should be silent. If the noise is still there in fifth, the coupling may be incorrectly put together. Jim

Just to clarify, do you mean you replaced all bearings on all three shafts in the transmission?

I'm surprised that IH is selling the double ball bearing. Last one I bought from them was still the roller type.

We did put on of the double ball bearings (bought from an aftermarket source) into an M to see how it would hold up and so far so good.

The deal with the bolt: The original design was two separate parts and the bolt and washer kept the rollers and cage from walking into the end of the input shaft. With the double ball bearing all the parts stay put and the whole assembly doesn't have anywhere to go to and so the bolt is not needed and IIRC there is no longer room for it.

As Jim said, if the gears have created a pattern via dirty oil and worn bearings and then you put in new tight bearings then the pattern is disturbed and it makes some noise.

I had a similar thing happen on a Super M, but the noise source was primarily the ring and pinion. I had replaced every bearing and had made the best attempt at matching the existing pattern on the ring and pinion. I may tear back into it sometime and re-shim the thing.

In neutral though it hardly makes any noise. Since yours is making noise even in neutral that's why I ask if every bearing in the trans has been replaced.