FSM gear box double lipped seal installation

[FarmallM51]

I understand that a special tool is required to successfully install the double lipped seal between the gear box & rear end to stop the rapid draining of lubricant from gear box to rear end. In the USA, is this tool usually available at Ford (New Holland) dealers? Thanks.
Marlin

[Billy26F5]

You would be very lucky indeed if a dealer still had the special tool. You can do it without the special tool provided you're very careful not to damage anything.
Sandy

[mathias1]

The double lip is only for the new performance super major. I did make a post about this a while ago

[Billy26F5]

I can't find any reference to that, if it's a single lip seal the lip must face the gearbox; Ford always had special tools for fitting seals.
Sandy

[shepp]

The post that Mathias refers to is "PTO gearbox seals" by him on Monday April 13th 2020. I made a response that gave the information about the 2 types of seal.

The double lipped seal is 89mm outside diameter and 44.5mm inside diameter and is ONLY fitted to the New Performance Super Major PTO gearbox, the output shaft on these PTO gearboxes reduces diameter at an earlier point than the earlier Super Major, Power Major and Major PTO gearboxes. These earlier PTO gearboxes use TWO single lip 89mm outside diameter by 54mm inside diameter seals fitted back to back, with the lips of the front one facing forwards towards the front of the PTO gearbox and the lips of the rear one facing backwards towards the rear axle. The front one seals the gearbox oil from the rear axle and the rear one seals the rear axle oil from the gearbox.

It is possible with some considerable effort to drive the later double lipped seal over the larger output shaft on the earlier PTO gearboxes and thus incorrectly fit this later seal to the earlier gearboxes, and some people have done this as the parts suppliers do not make it clear which seal is for which tractor, probably because they do not have a clue! When incorrectly fitted like this, the double lipped seal very quickly shreds and you are back to a full strip down job again!

A new seal can be driven home into the gearbox case with a tubular drift slightly less than 89mm diameter, the trick is to avoid damaging the seal lips as the seal passes over the splined ends of the PTO gearbox output shaft either by using a suitable diameter plastic tube or some PTFE tape temporarily wrapped over the splines.

[SvendH]

Is it possible to split at the rear-end flange,leaving the gearbox attatched to the engine.And so replace pto seal?
Svend

[Billy26F5]

To replace the PTO seal you just lower the PTO casting having pulled out the extension shaft some 6" or so, no need to split anything. When doing the main seal you do need to do as you say.
Sandy

[shepp]

Hi Sven

I would think it will be a very difficult job to do this. Even if the opening in the back of the gearbox casting is wide enough to allow the seal diameter to pass through, there is still the issue of how to extract the seal(s) from the PTO gearbox tunnel and along the output shaft, it will probably sit about 100mm back, perhaps more. You would have to use some sort of strong hook arrangement to try and hook behind the outer rim of the seal. The conventional way is to remove the PTO gearbox after withdrawing the PTO extension shaft, remove the front cover and after removing the circlips drive the shaft complete with rear bearing and seal(s) out of the housing.

If it were possible to replace the seal by splitting between the gearbox and rear axle, then it would have the advantage of being able to replace the main gearbox output shaft seal at the same time. Working on the basis that the main gearbox output shaft seal OUGHT to be replaced at the same time as the PTO seal(s) as both seals may be causing the issue of oil transfer from the gearbox to the rear axle, then there is nothing lost by splitting the tractor between the gearbox and rear axle, doing the gearbox output shaft seal, and checking if the PTO seal(s) can be done as you are enquiring. If not then it is easy enough at that stage to remove the PTO gearbox to do the seal(s).

Let us know how you go on if you decide to try this approach!

[SvendH]

Mine is a early Super with single plate clutch and transfers about 10 liters per year.So i was thinking of trying whats easyest first !

[Billy26F5]

You can see if it's the main seal or the PTO seal by seing if the leak stops when the level goes below the main seal or not, if it does stop you only need to change the main seal, if it doesn't stop leaking do the PTO seal first and do this test again. Doing both will ensure longer duration before one goes again, but might not be the easiest way of doing it if you're in a hurry to have your Major in use again.
Sandy

[SvendH]

Is the main seal accessable if you split at the bell-housing then?

[mathias1]

Is the main seal accessable if you split at the bell-housing then?

No, You need to split at the rear. It's not that difficult to do, unless you have a County conversion
But you can do the pto box first, and see what it does. While you are there renew also the seal at the pto box handle.
If you split at the bell-housing it's very easy to replace the seal of the ingoing shaft. This one will need a replacement too at some point.

[SvendH]

Thanks guys

[shepp]

The easiest way is to do what most people do - keep pumping oil from the back end into the gearbox on a regular basis!

I think it is fair to say that when the PTO seals start to leak down the gearbox output shaft seal is going to take a bit of stick. That back end casting is a cavernous affair and a good half of the the four and a half gallons of oil in the gearbox can drain into the back axle fairly quickly, resulting in the gearbox seal running in semi dry conditions relying on oil splash from the gears. If the PTO seals have been leaking for a while it is almost inevitable that the gearbox seal will need replacing as well.

John Deere adopted a split level system on the 50 series tractors, with the gearbox oil at a higher level than the rear axle, supposedly to reduce oil drag and parasitic power loss in the transmission. One or two tractors I understand did develop gearbox issues when the seals failed and the gearbox drained down, the same gearbox fluid is of course also used in the Power Synchron 2 speed shift. Some people thought the 40 series was better for not having this split system, they were both a good range of tractors.

[SvendH]

I will keep that in mind Shepp !
The oil seems to leak down to about level with the upper gearshaft where it stabelizes,so perhaps as Sandy says it is the main seal thats the most leakey?

[FarmallM51]

Thanks for all the help. This discussion helped me understand the seal differences & diagnosis. Since the rear end oil is so low that I can see the lower main shaft through the transmission filler, I'm assuming the pto seal is the culprit, and that I can change that without splitting the tractor. From the parts manual that I have, it appears that the Agriline #80250 (I hope that is a pair) is the correct shaft seal (E1ADKN-7297-B in the parts manual) and #6234 is the shifter seal.
Marlin

[FarmallM51]

In the diagram that I have, the PTO seals look like they are nested, one inside the other & the parts manual lists the number (E1ADKN-7297-B) as a pair. Is this correct, or do I need to order 2 seals & place them back-to-back?

[shepp]

If your tractor is a Major, Power Major or early (blue/orange) Super Major prior to serial number 08C960337 then Agriline 80250 seal 89mm x 54mm x 12.5mm is the correct one, but they are listed individually at £7.02 each including vat so you will need to order 2. You also need to order Agriline 6234 seal for the selector shaft at £6.00 , and you will need a new large "o" ring that Agriline does not list which seals the PTO housing to the rear axle, these are available from Dunlop Tractor Spares and I think Malpas Online might list it as well. These last two companies do the oil seals as well.

One thing that no one lists is the paper gasket between the PTO gearbox housing and the main gearbox, if the old one is damaged you will have to make a new one up from gasket paper which is available from a few suppliers on EBay. Use a good gasket cement such as Blue Hylomar on this paper gasket.

[FarmallM51]

Can the seals be extracted from the PTO gearbox & replaced without dismantling the gears, bearings & shafts? Thanks.
Marlin

[Billy26F5]

It's possible but very difficult, shepp's procedure is much easier and less likely to damage the seals.
Sandy

[AdrianNPMajor]

viewtopic.php?p=51784#p51784

[SvendH]

viewtopic.php?p=51784#p51784

Very usefull

[FarmallM51]

Is there an easier way to remove the circlip from the shaft, than to lever it off with a screwdriver? Thanks
Marlin

[Billy26F5]

If you have circlip pliers try them, otherwise battle on with the screwdriver.
Sandy

[Roadless63]

I'm pretty sure there is the option of fitting either a double lipped seal or 2 single lipped seals back to back on earlier tractors in the pto drop box. On the np I think only a double lipped was available and it is a different size to earlier e1a tractors.
The only successful way to change the seal is drop the pto drop box (drain oil from gearbox and back end first) then strip pto pot to change seal(s)