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live grive gearbox

Posted: Fri Nov 20, 2020 6:01 pm
by hazzard
Hi,
I have acquired a live drive gearbox to replace a dead drive one in my 1962 super major. It comes complete with dual clutch which is in great condition.

Not being conversant with this type of work are there any things that I need to know about the fitting? I well need new gaskets to fit gearbox to bell housing and are there any other seals/bearings that give trouble which I should replace while I am in there ?
Thanks in advance.

Re: live grive gearbox

Posted: Fri Nov 20, 2020 6:28 pm
by Billy26F5
Check for leak evidence in the bell housing. Remember to get a flywheel too. Otherwise just swap the gearboxes, making sure not to loose the rollers on the bearings (don't mix them or you'll find yourself in there again very soon); clutch and flywheel.
Sandy

Re: live grive gearbox

Posted: Fri Nov 20, 2020 7:48 pm
by hazzard
Will I need to get a new flywheel for the dual clutch ?

Re: live grive gearbox

Posted: Fri Nov 20, 2020 9:48 pm
by shepp
I would definitely fit a new gearbox output shaft seal, this is in the housing held by four bolts on the back of the gearbox, and I would most definitely change the two PTO auxiliary gearbox seals that are fitted back to back in the PTO auxiliary gearbox - you will have to unbolt the PTO auxiliary gearbox from the bottom of the main gearbox to do this. When re-fitting the PTO auxiliary gearbox use a new gasket and a new large "O" ring, these are available from the spares people such as Dunlop Tractor Spares and Agriline etc. I would have a good look at the input shaft seals, there is one on the transmission input shaft and one on the PTO gearbox input shaft, buy a cheap manual such as I & T to help if you are unfamiliar with the layout, it is easier to renew them at this stage than later on when everything has been reassembled! The large gasket between the gearbox and rear axle is unavailable and if yours is damaged you will have to tap one out using a large sheet of gasket paper, gasket paper is available online and on EBay. Use a good quality gasket cement such as Blue Hylomar on the gasket and casting faces.

Re: live grive gearbox

Posted: Fri Nov 20, 2020 11:31 pm
by Billy26F5
You'll need a dual clutch flywheel, which has a space for the clutch, the others don't.
To change the gearbox output shaft seal is a huge job, as you'll need to split the transmission as well and adjust the pre-load once you've changed the seal. The PTO seals are easy as the casting has to come off anyway to remove the gearbox.
Sandy

Re: live grive gearbox

Posted: Sat Nov 21, 2020 9:32 am
by mathias1
Good luck doing the swap. Just to be sure you didn't buy a live drive from a new performance. Just check the outside of the pto drop box is the same.

Re: live grive gearbox

Posted: Sat Nov 21, 2020 1:42 pm
by shepp
As the gearbox is being changed to a live drive version the original gearbox will have to be detached from the rear axle anyway and the replacement live drive gearbox will come loose and thus replacement of the rear output shaft seal on this gearbox before it is fitted will be an easy job!! There is no pre-load to set on the upper output shaft bearing because it is a parallel roller bearing, the end nut with the pinch bolt in it is simply tightened up against the oil seal sleeve then secured with the locking tab and the pinch bolt tightened. The pre-setting comes in on the tapered roller bearing on the differential pinion shaft not the gearbox output shaft!

Changing this seal on an an assembled tractor is not particularly difficult, there is just an amount of dismantling to be done before splitting the gearbox from the rear axle casing. I have done these before by letting the gearbox and rear axle part an inch and then fitting 2 long high tensile bolts to each side with a nut either side of the gearbox casing, the bolts keep the alignment in place as the front end is moved away on the trolley jack. You only need a gap of about 20cm to work through to undo the output shaft nut and then the housing containing the seal. The bolts guide the lot back together again.

A further pair of seals I would change before reassembly would be the brake cross shaft seals, one on each side, again an easy job when everything is already dismantled.

Three types of flywheel were fitted, one for the standard 11 inch clutch, one for the single plate heavy duty 13 inch clutch, and a different one again for the live twin plate clutch, so yes, you will have to change the flywheel.

Re: live grive gearbox

Posted: Sat Nov 21, 2020 6:48 pm
by Billy26F5
Are we sure we're looking at a complete gearbox unit or just the internals? If it's the latter it's a far bigger job to do the output seal. I definitely vote in favour of changing cross shaft seals, as they can be very irritating when they leak (I know this from experience). Agriline has them, they can be changed without splitting the transmission.
Sandy

Re: live grive gearbox

Posted: Sat Nov 21, 2020 8:01 pm
by shepp
Well Sandy, I am assuming that it will be a complete unit, if the internal primary gearbox is taken out of an assembly then the rest is not much use to anyone else! Not many people will be aware that it is possible to do this in any case. Perhaps " hazard " can enlighten us?

Re: live grive gearbox

Posted: Tue Nov 24, 2020 6:48 pm
by hazzard
Thanks for all the replies.

The gearbox is a complete unit. On the present set up (dead drive) I am losing oil from the gearbox and presume that it is leaking from a seal on the output end of the gearbox and is then coming out of the split pin in the bell housing.
With this in mind I will want to change the seal that is causing the leak (in the dead drive box) in the live drive box so that I don't have this problem again.

All advice welcome please !

Re: live grive gearbox

Posted: Tue Nov 24, 2020 7:29 pm
by Emiel
Hi,

In the live box it are two seals around the input shafts and one gasket on the input shaft housing. Just unbolt the housing and take apart the input shaft and the seals. If I remember correctly there is a needle bearing in between the shafts. Check whether this is still ok.

Leakage from the clutch housing often is motor oil. Your nose can help you determine that before splitting. When the flywheel is of and the tractor splitted replacing the bottom halve of the crank seal is not a really bad job.

The gaskets you can easily make out of gasket paper and with a little liquid gasket you’ll have a perfectly leak free joint.

Don’t forget to put a new pilot bearing in your flywheel.

Rgds emiel

Re: live grive gearbox

Posted: Tue Nov 24, 2020 7:58 pm
by Billy26F5
If the oil is coming out of the bell housing, it means it's from the input end. If it's coming out the output end the level in the rear transmission would rise. Engine oil is black, so it's easy to see what's leaking.
Sandy

Re: live grive gearbox

Posted: Tue Nov 24, 2020 8:31 pm
by shepp
It is more likely to be engine oil coming out of the bell housing split pin. As Sandy says it will be black and smelly if it is coming from the engine, if it is oil coming from the gearbox input shaft seal it will be cleaner looking. When you split the engine from the gearbox you will he able to see better where it is coming from. If it is engine oil then you kneed to consider how much is leaking to determine how to proceed. The bottom half of the seal could be replaced whilst the engine is split from the gearbox by removing the sump and replacing the bottom half of the seal located in the sump. The seal is a rope seal in two halves, to replace the top half involves an engine strip down and removal of the crankshaft. Replacing the sump half is a little involved, you need to consider how bad any leak is before deciding. Get a manual such as I & T from Technical Publications Services to help.

Whatever you decide on the engine seal (if it is that which is leaking), you can easily replace the two oil seals on the live drive gearbox input shafts before you fit the gearbox. One of them is a small diameter seal located IN the larger diameter outer pto drive input shaft, this seals the smaller diameter inner transmission drive shaft. The other is a larger seal located in the input shafts housing that seals the larger diameter PTO input shaft. Between the two shafts as emiel says is either a needle roller bearing or a phosphor bronze bush.

Before fitting the gearbox it is a MUST to replace the two back to back oil seals in the PTO auxiliary gearbox and the gearbox output shaft seal in the housing held by 4 bolts on the back of the gearbox, these ARE known to fail regularly and when this happens oil in the main gearbox - which is held at a higher level than oil in the rear axle - then seeps from the main gearbox into the rear axle resulting in the main gearbox having to be regularly topped up to a full safe level.

Re: live grive gearbox

Posted: Wed Nov 25, 2020 4:49 pm
by hazzard
Re shepps response about the 2 oil seals in the PTO auxiliary gearbox I took the super major topping yesterday, no problems, and it was hard going in very thick grass and feg.
When I got home I parked up and this morning there was a large pool of oil under the gearbox drain plug. It seems therefore that shepps advice about changing the 2 oil seals is the way to go because this is obviously where the oil is coming from,
New gearbox steam cleaned today, will remove as much paint as I can then undercoat it after changing all the seals/bearings previously mentioned. Then top coat then assemble!
Many thanks for all your comments, they are all much appreciated.
H

Re: live grive gearbox

Posted: Wed Nov 25, 2020 7:44 pm
by shepp
Hi

The oil seals I am referring to in the pto gearbox prevent oil from moving from the gearbox to the rear axle and vice versa, in other words INTERNAL oil movements. If you have a pool of oil under the tractor is it black oil? If so it has come from the engine rear oil seal behind the flywheel and will have drained out through the hole with the split pin in the bell housing. If it is clean oil then it will be gearbox oil and this may have come from either the gearbox input shaft oil seal and drained out through the bell housing hole with the split pin, OR from a leak from the gasket or large rubber "O" ring that seals the PTO gearbox to the underside of the main gearbox, this will have simply drained directly from the joint. If it is the latter you should be able to see where it is coming from.

Whatever is happening with the old gearbox renew all the seals as advised on the new gearbox before fitting it to the tractor.

Re: live grive gearbox

Posted: Thu Nov 26, 2020 11:52 am
by hazzard
Thanks shepp all parts ordered and will be fitted next week if time permits !

Re: live grive gearbox

Posted: Sun Nov 29, 2020 4:01 pm
by hazzard
Following on from identifying the oil leak can the forum please advise how to fit the two oil seals in the pto selector underneath the gearbox which is where the oil is leaking from in the dead drive box? I'm told by people who have done it before that it's not straightforward! Thanks.

Re: live grive gearbox

Posted: Sun Nov 29, 2020 8:20 pm
by Billy26F5
There's only one seal in the PTO casting, there's an o-ring and a gasket between it and the gearbox. You'll need to be very careful with the new seal, as there isn't much room in there. The selector seal is easy.
Sandy

Re: live grive gearbox

Posted: Sun Nov 29, 2020 11:49 pm
by shepp
Is the oil coming from where the shaft attached to the PTO engagement lever enters the PTO gearbox housing? If so that is a small seal readily available from Agriline and other suppliers. It is easily changed by undoing the operating lever bolt and nut, clean up the protruding shaft of all paint and rough or sharp edges, drain the gearbox oil from the drain plug under the pto gearbox into a clean container for re-use, remove the old seal carefully with a screwdriver blade and evenly tap in the new seal with the spring and lip to the inside of the PTO gearbox. Replace the drain plug and re-fill the gearbox to the filler level plug.

If the oil us coming from the joint between the PTO gearbox and the main gearbox, then that involves the gasket and a large "O" ring being replaced at the joint between the 2 gearboxes. As the whole gearbox assembly is being changed there is no point in repairing the leak at this stage.

The two oil seals I refer to are IN the PTO gearbox and stop oil from being transferred from the main and pto gearbox to the rear axle and vice versa. When they fail this does NOT let oil leak to the outside of the gearbox, you only know they have failed because the main gearbox oil level keeps going down as oil is able to flow from the gearbox to the rear axle. To renew them you have to detach the PTO gearbox from the main gearbox and dismantle the PTO gearbox. It is not that difficult a job, get a cheap manual such as the one from Technical Publications Service or Agrimanuals or Agriline or many other suppliers, they are only about £12 to £15. These are the seals you are well advised to renew in the replacement live drive gearbox and PTO gearbox assembly before you fit it to your tractor. So you will have to split the PTO gearbox from the main gearbox on the live drive assembly, replace these seals and the pto selector shaft seal, refit the PTO gearbox to the main gearbox using a new gasket and large rubber "O" ring, replace the output shaft to the rear axle seal, replace the brake cross shaft seals in the rear axle casing, then fit the replacement live drive gearbox and PTO gearbox to the rear axle. Get a manual and familiarise yourself with the layout of everything, it's well worth the few pounds they cost.

Re: live grive gearbox

Posted: Mon Nov 30, 2020 12:51 am
by Old Hywel
I’ve vague memories of a persistent oil leak from a Super Major bellhousing. It was plainly gearbox oil, so the tractor was split, gearbox input shaft seal replaced, and reassembled. When it still leaked, we deduced that it must be the small seal between the shafts which was faulty, so this too was replaced. The bellhousing was thoroughly cleaned before the tractor was loosely assembled, enough to enable the engine to run. After a couple of minutes the engine was stopped, and tractor split once more (we were getting good by then). There was a trail of fresh oil coming from a small drilling on the face of the gearbox, which should have been sealed by a small cup washer/core plug lying on the base of the housing.
If I remember correctly, the hole carried a selector shaft of some description, and was obviously below the oil level in a stationary gearbox.
Leaks don’t always mean new rubber seals.

Re: live grive gearbox

Posted: Tue Dec 01, 2020 8:54 pm
by hazzard
What a wealth of knowledge there is on this forum thanks to all people who have responded. I've finally got the box down to bare metal and undercoated with red oxide. Ive identified the cup/washer that old hywell refers to and it is firmly in place so no worries there.

The input shafts are a lbit 'wobbly' so need investigation


So its coming along and i just need to make gaskets for the removable parts, fit them and paint toocoat blue.

Anyone looking for a used flat belt pulley?
Many thanks to all. H.

Re: live grive gearbox

Posted: Wed Dec 02, 2020 12:45 am
by Billy26F5
The input shaft is wobbly because the pilot bearing isn't supporting it, just make sure that it turns nicely.
Sandy

Re: live grive gearbox

Posted: Wed Dec 02, 2020 9:50 am
by hazzard
Hi Sandy are you suggesting that if the pilot bearing isnt supporting the shaft then it needs replacing ?

Re: live grive gearbox

Posted: Wed Dec 02, 2020 12:34 pm
by Billy26F5
I assume your previous post was before you assembled the gearbox, if so you can't support the front of the shaft, as the pilot bearing is in the flywheel.
Sandy

Re: live grive gearbox

Posted: Wed Dec 02, 2020 6:32 pm
by hazzard
The gearbox came to me complete, and with a dual plate clutch. My experience with a major box is with my super with a dead drive box which has lost all its oil through seals in the pto box so i am going through live box to avoid same thing happening again and to paint it.
I have pto box oil seals and o ring and was concerned that the smaller input shaft was quite wobbly.
Any advice regarding that issue very welcome thanks.