Gearbox noises

[Stu_Fletch]

Since I've owned my diesel major it's always had a noisy and graunchy gearbox/backend and people have always told me that's just how they are but it seems to be getting worse, it just used to be on the road but it's even doing it now whilst ploughing, the vibration is travelling up through the wings and is unbearable on the road now, caused by the wings drumming at anything over 1200 rpm had anyone got any ideas where the best place to start may be I don't want to miss something obvious.
Thanks in advance

[henk]

Hard to say,
I would put the rear axles on brackeds so the wheels are free and let them turn in different gears and at different rpm's and then feel and listen. Maybe you can found out if it is a bearing of the rear axle or the brake axle or maybe in the rearend.

[Stu_Fletch]

Thanks Henk Yes when using the left brake it makes a bang as if it's taking up alot of backlash and also changing direction... I'd never thought of that! How do you go about stripping that out.. Is it a top cover off job? Ps I've changed the backend oil and checked the magnets and found nothing

Cheers

[henk]

Are we talking New/Power Major or Super Major?
On the New/Power mMajor,
Check the hexagon nut on the inside of the fender on the brake drum. Mine was loose at the time I bought my tractor.
You could remove the rear wheel and openup the brake unit.

[Stu_Fletch]

It's a Diesel Major Henk

I've managed to spend a couple of days on it and managed to strip everything out of the rear transmission and found the diff had lost it's pre-load on the bearings and was now baggy which unconvincingly I assumed that was the cause for my noises after I stripped the diff to find alot of play in the thrust washers on the pinion gears.... should there be a groove in both castings or have they worn badly?.

Since something was nagging me it was more than that, I drained the gearbox oil and found plenty of brass shavings. So I removed the selector cover on the gearbox and instantly found the fault, the bush that fitted inside the reverse shaft selector gear had been floating round and pretty much disintegrated whats left isn't much use to anyone!













Cracked thrust washers


Pinion thrust washer wear




Old Bearing


New Bearing






Reverse gear shaft bush


https://www.youtube.com/watch?v=2i8P2-SIvTU

https://www.youtube.com/watch?v=wLqUW5_kxVg

https://www.youtube.com/watch?v=qeua8NDR0p0

So now I need to split the tractor and get the gearbox out and see if i can get an original bush, or get one made, thoughts and suggestions as always would be greatly appreciated

Cheers

[super6954]

Hi Stu
I guess you found the problems, Kinda looks like she's "cream crackerd" . I guess 50 odd years of abuse haven't been kind to her . I went back through your pictures after looking at your video's. I see she's still a dead drive tractor. Maybe now that gearbox/back end is shot, it's a good time to find a live drive gearbox and casing, another backend and clutch/ flywheel and convert her over . Mine was live here i put the same motor in, 75 hp should be no problem for the live gearbox & a good clutch assembly , one of my powers has got a 90 hp 6d in it . It would make that a very usable tractor for ploughing and anything else using the 3 point hitch.

I didn't think you had Jersey cows on the farm there either from your Dyno videos , it kinda looks like one dumped an udder full of cream in the gearbox to . I guess those filings have been round in that rear end oil for quite a while. The major hyd pump suction screens only good for Fish about 4 lb's and larger in terms of what it will catch before it enters the system, so that might not be good either for any other bearings in there .
Good luck with what you decide for a plan, i really think you'd like the live drive conversion to .
Regards Robert

[AdrianNPMajor]

Hello Stu
Excellent detective work. The gearbox is retrievable, but I agree with Robert re the rear axle. You could try and source a replacement diff and its matching drive pinion, but once you find them, you may as well use the rear axle they come in.
Very informative photos and videos.
Best, Adrian.

[henk]

Seems you run into some serious problems. Hope you can solf them.

[Stu_Fletch]

Another quick update I've split the tractor and stripped the gearbox completely, and took the shaft and gear to a chap who is going to make and fit me a new bush. I've got 3 new ball bearings as they were pitted and noisy. I've rebuilt the bull pinion shafts with original bearings and new seals. just a few issues I've got that i can't find the answer to...

What size is the gearbox drain plug as I can't seem to find anyone selling one?

Does the gearbox need to be stripped to reseal the top shaft which is common for leaking or can i do it at a later date as I've only got it split at the bell housing at the minute and don't want to split it again otherwise supporting the naked transmission housings is going to get a bit precarious?

What size are the toggle bolts on the clutch that the thrust bearing runs against to actuate the clutch, as mine are worn right down to the toggle arms?

When i get a few minutes i'll upload some more pictures.

Cheers

[AdrianNPMajor]

Hello Stu
You can leave the upper gearbox seal for another day when you are able to split the tractor between gearbox and rear axle. Once split, it's any easy job. Photos to follow if you need them, which you won't!
Sorry I can't answer questions 1 & 3.
Looking forward to seeing photos of what you have done since the last update. I have never taken the diff apart so I was learning new stuff from your images higher up this thread.
Best, Adrian.

[Stu_Fletch]

Ah good I was hoping so Adrian. I just need to get it back on the road for this autumn which is looking like a fair task at the moment with the little spare time i get.

So as you know I've got the gearbox out and stripped it, the reverse gear is away being re-bushed, So here's some pics of the bull pinion shaft housings being assembled with new seals.

As you can see here I need to source some bolts for these toggle arms.






New Inner oil seal fitted




Original bearings fitted as they are like new


All greased up


New Outer drum brake grease seal fitted


Cheers

[AdrianNPMajor]

Textbook stuff.
Have you noticed that when you unbolt a piece of Major, however small it is, the piece still weighs a hell of a lot! Chunky bits of kit.
Best, Adrian.

[Stu_Fletch]

Another update but this time with some bad news So I've spent a lot of time on it lately and got it nearly all back together less the footplates, fenders and rear wheels, I've had it running today on axle stands in all gears for about 20 mins but when I ran it in high 3rd after about a minute the engine suddenly started to load and die, I de-clutched it luckily instantly as I had no idea where the fault was and tried to get it out of gear but it was stuck solid I though maybe it had jumped into another gear somehow at the same time. I drained the gearbox oil back out and removed the selector cover to my surprise it was only in one gear - 3rd I the tried moving it back into reverse and realised the reverse gear bush that I have had made has picked up and seized onto the lower shaft So it's all got to come to bits again

Anyway the bit where I need help is with this bush. The possibly original one may have been drilled and this one is solid. The new bush had been made to be a 0.004'' press fit in the gear and have 0.004'' clearance on the shaft it spins on, my machine shop suggested this we had no measurements to go on and that this was in his eyes standard practice.

Is there anyone with engineering experience that can advise me on what clearance it should have had or need to have had other than just a bit more 'DOH' I'm shocked it has happened as it was so well fitted onto the shaft with no tight spots. Above in the pictures you can see there is a spiral grove to lubricate the bush although i can't see how it can pass it through as there is a dead as it cant pass though the next gear.

On the plus side I have modified the relief valve in the hydraulic chest the same as Brian demonstrated in his youtube video and set the max pressure it work wonderfully although after fully resealing all the hydraulics the lift still drops

If anyone could be of any assistance i would greatly appreciate it

Cheers

[scoobyjim]

With regards to the bush i would suggest the clearance is ok but it will need the oil way to enable the bush to run on oil. Without it it will run hard against one side.