Why am I losing oil from my transfer box breather?

[fv1609]

On the pig, the gear box is connected via a prop shaft to transfer box at the rear which is mounted in front of the rear diff. It permanently feeds another prop shaft to the front where FWD can be selected.

 

I am losing oil from the transfer box breather & after a run of more than 5 miles the transfer box feels a lot hotter than the diff, but I don't know if that is normal.

 

The trouble started last year. The TF/box oil level was going down & was ending up in the diff. No external leakage at all. The TF/box breather was not blocked or damaged it seemed.

 

During the winter, I removed the TF/box. Although the main seal from the TF/box shaft to the diff looked good, I replaced it.

 

This year after it had a good run of 35 miles found I was losing oil through TF/box breather. I replaced the breather & in case the diff was pressurising removed the diff breather.

 

Still got oil leakage. So to get me to Kemble (65 miles) I put a breather pipe 18" long up from the breather hole. No external leakage but oil still getting blown out of the tube.

 

I drained the TF/box & found pieces of metal. Dismantled the box & found a mangled spacer washer (3.5in od, 3" id). I think I messed up as it was tight on reassembling the shaft.

 

I had what I believed to be an OK TF/box on another chassis & fitted that. After 5 miles no leaks but after 12 miles, leakage through the breather & diff feeling much hotter than the diff, just as before.

 

It is not stuck in 4WD. The oil is OEP220 as indicated in Servicing Schedule & stencilled on the side of it. It came from a sealed military drum of recent manufacture.

 

I was at show recently & saw a Humber GS. I asked if he had leakage problems, apparently not. But I could see the TF/box smothered in old oil & on checking the level found his TF/box was empty.

 

So any ideas please?

 

& why do these things have to happen mid-season

[MiketheBike]

Clive,

I have to admit, the transfer box on my ferret gets pretty damn hot, so maybe that is normal?

Maybe the diff is sucking oil from the transfer box? Does that also have a breather.....maybe the temp difference between the two is a factor there?

[fv1609]

Oh so normaly on the road it only drives the rear wheels ( 2WD ) so you should not be suffering heat build up due to wind up in the t/fer box.

Is the problem heat or just the oil being expelled through the breather, is there a baffel missing below the breather ? like you get on some rocker covers on cars !!!!!

Is this a widespread problem, do others suffer from it, are you over filling it ?

 

 

2WD most of the time I am not stuck in 4WD.

 

The TF box is intact there are no baffels.

 

It is being filled up to the correct level

 

I have inspected 4 Humbers over the last few days & they are expelling oil from the breather.

[fv1609]

Clive,

I have to admit, the transfer box on my ferret gets pretty damn hot, so maybe that is normal?

Maybe the diff is sucking oil from the transfer box? Does that also have a breather.....maybe the temp difference between the two is a factor there?

 

 

Nobody seems to be aware how hot their TF/box gets. But clearly is too hot & is being boiled/frothed out of the breather.

 

Last summer there was no external seepage as the TF/box was losing oil to the diff. Replaced the main seal, which cured it now got the breather loss problem.

 

Over the weekend have obtained 4 opinions, 3 of which are from ex-REME. Suggestions have been:

 

Use engine SAE 50

 

Use engine SAE 30

 

Check that the gasket between the diff & TF/box is not missing as blue goo may mean the TF/box gears/bearings are getting pushed sidewards & being loaded. But I can see no evidence of diff spline marks going beyond their normal position in the female end of the TF/box shaft. I was able to reuse the original paper gasket, so it has not closed up like using a blue goo.

 

Although SAE 50 & 30 are less viscous, there will be more friction. Someone suggested that Saracen or Saracen had an instruction to add a molybdenum agent to some components for this sort of problem? I'll need to look at some EMERs/Servicing Schedules or does anyone know?

 

So would some friction reducer be an appropriate addition? If so what?

[fv1609]

Well the original TF box is now rebuilt. Seems to turn nicely & the propshaft that goes to the front wheels for selection to 4WD, turns freely when it is in 2WD. So it is now installed again.

 

http://img.photobucket.com/albums/v684/fv1620/Dscf4373-1.jpg[/img]

 

But same trouble, oil is still being lost from the breather. Plan B was to tap a hole for an alternative place for the breather 2 inches higher up, with due regard to the architecture of the casting inside, it is a fairly sheltered from the direct squirting of oil from the gears. But oil is lost just as readily from this higher breather position.

 

http://img.photobucket.com/albums/v684/fv1620/Dscf4327a.jpg[/img]

 

Although OEP220 is what was used in service as required by the Servicing Schedule, some have suggested that there is no anti-frothing agent in OEP220 but there probably is in an EP90.

 

This all sounds very reasonable. But I doubt if most privately owned Humbers get treated to OEP220, the owners will be using EP90 yet still they have breather leakage problems.

 

I am wary of using a thinner oil as this will increase wear, but was still thinking of an additive.

 

Looking at the Saladin Servicing Schedule new transfer boxes at the 500 mile service have OX320 added to the OEP220. So that it is present in 10% concentration.

 

OX320 is 90% mineral oil & 10% colloidal graphite. Anyone any experience of adding graphite additives in anything?

 

 

[andyroo]

 

Looking at the Saladin Servicing Schedule new transfer boxes at the 500 mile service have OX320 added to the OEP220. So that it is present in 10% concentration.

 

OX320 is 90% mineral oil & 10% colloidal graphite. Anyone any experience of adding graphite additives in anything?

 

 

 

I tryed getting a drum of colloidal graphite, when I finaly found a supplyer the quote was just out of this world :schocked: Over £200 plus carrage plus VAT.. That was arround 6 maybe 8 years ago so no idea what it is now. I've been using Fuchs 'Molycent Concentrate' and although it was arround £130 for the 25 Ltr drum we still have 2/3's of it left. We add arround 5% only when we do an oil change. We top up with plain oil. Been using EP90 for all bevel gears from day one. The Moly dose help with noise reduction.

 

 

[R Cubed]

 

Oil is OEP 220 as painted on TF/box & stated in Servicing Schedule. It was from a sealed drum of genuine military stuff & has been used to fill up the diff & tracta joints.

 

 

Is this oil new in the drum, could the sealed drum have suffered from condensation and got in to the oil so when it's very hot the water in the oil boils and froths the oil ????

My GMC transfer box gets so hot you can only just bear your hand on it and that does not expell oil out of the breather, it has Morris AG90 in it no bronze eating additives.

[ArtistsRifles]

<snipped>

Looking at the Saladin Servicing Schedule new transfer boxes at the 500 mile service have OX320 added to the OEP220. So that it is present in 10% concentration.

 

OX320 is 90% mineral oil & 10% colloidal graphite. Anyone any experience of adding graphite additives in anything?

 

</snipped>

 

 

Nearest I've heard of is a product called "Achesons Oil Dag" - and to quote Richard Notton from the Stolly owners list - "it's gob-smackingly expensive".

Which agrees with what Andy said!!

[fv1609]

OK thanks everyone.

 

Andy, so less noise must mean less friction & less heat. Expensive! I would only need 1/3 pint. I wonder if the are small quantity suppliers?

 

R3, the drum was full & had a plastic seal built into the nozzle. Thinking about it the first fill up was in the winter with EP90 as I bought the OEP220 in April. Most people use EP90 & they seem to get loss through breather. But other Humber owners seem more relaxed (or unaware) of this issue than me! AG90 is that an extreme pressure oil though?

 

I notice Bedford MK & R series use OC600 in the TF/box. That is mineral oil with 6% rape seed oil. But I see the spec says not for hypoid gears.

 

Neil, expensive indeed. Richard does come on this forum & maybe add to this, but I think he has his hands full at the moment with other things.

[andyroo]

OK thanks everyone.

Andy, so less noise must mean less friction & less heat. Expensive! I would only need 1/3 pint. I wonder if the are small quantity suppliers?

 

 

Clive,

 

I'll try and remember to bring a small quantity to Dorset for you. Only 19 days to go :-D

 

[Richard Farrant]

AG90 is that an extreme pressure oil though?

 

I notice Bedford MK & R series use OC600 in the TF/box. That is mineral oil with 6% rape seed oil. But I see the spec says not for hypoid gears.

 

 

 

Clive,

 

AG90 is a Morris's oil and is a Straight SAE90, ie not EP / Hypoid.

 

I note your comment on Bedford MK and R types used OC600 in the transfer box, I do not think this is correct, if this is from a servicing schedule it could be a mistake or possibly for tropical use. The correct oil specified by Bedford in the MK transmission manual is a Straight 90. OC600 is/was a Straight 140

gear oil, often used in axles with worm and wheel drives, etc. I recollect the use of OC600 was basically phased out years ago, but occasionally an elderly vehicle or piece of equipment would appear, which required it.

 

The oil for the Beddy transfer boxes was, I think...... OMD330, which is a SAE50 engine oil and often specified for gearboxes, it is equivalent to a Straight 90 gear oil, the calculations for SAE gear and engine oils worked out on a different scale.

 

 

 

 

 

[fv1609]

Andy that would be very kind of you. What I was hoping to find was some similar product I could buy off the shelf in a small quantity that might be used in souped up racers, tractors or something. The last show for the pig is next weekend (Purbeck) so would be nice to get something locally before then so it would be a nice test run.

 

 

Richard yes you are completely right. That is what comes of rummaging in the house with a torch (we have had no electricity for 3 months) looking in boxes for books. Then finding no proper paper & a biro with no ink in it, engraving this on the piece of cardboard. Coming back into the shed with PC in, no lights in there either, using same torch trying to read the engravings on the card with the now weaker torch, add dyslexia, not being able to find my glasses, stupidity with age, 3 glasses of wine & you have a recipe for bollox :oops:

 

But how do these other vehicles get away with straight engine oils in their TF/box? Any ideas for an off the shelf additive?

[Richard Farrant]

 

Coming back into the shed with PC in, no lights in there either, using same torch trying to read the engravings on the card with the now weaker torch, add dyslexia, not being able to find my glasses, stupidity with age, 3 glasses of wine & you have a recipe for bollox :oops:

 

But how do these other vehicles get away with straight engine oils in their TF/box? Any ideas for an off the shelf additive?

 

 

Clive,

 

Add to your list of problems, "hair in eyes" :tongue: :evil: :-D

 

Why not try Molyslip Gearbox Protector. Things have moved on since colloidal graphite additives, molyslip is molybdinum based and has a good reputation for anti-friction. The additive, OX320, we used in FV600 Alvis vehicles was withdrawn in the late Eighties as MVEE and Alvis were reported to have concluded it made no difference if added or not, according to a technical report recieved.

 

 

[fv1609]

Clive, Add to your list of problems, "hair in eyes" :tongue: :evil: :-D

 

"Hair in eyes"? Well I've got hair in ears now , I didn't know about the eyes.

[ArtistsRifles]

Clive,

 

Add to your list of problems, "hair in eyes" :tongue: :evil: :-D

 

Why not try Molyslip Gearbox Protector. Things have moved on since colloidal graphite additives, molyslip is molybdinum based and has a good reputation for anti-friction. The additive, OX320, we used in FV600 Alvis vehicles was withdrawn in the late Eighties as MVEE and Alvis were reported to have concluded it made no difference if added or not, according to a technical report recieved.

 

 

 

 

Thats interesting Richard - your namesake, Richard N. has, I think, a contrary view - I seem to recall him saying on the Stalwart forum over on Yahoo! that he's taken old wheel stations apart that had the additive in and found no sign of wear yet new ones running oil only were already showing signs of pitting etc.

 

Be interesting to see what he says when he has the time to return to the forum! :-)

[Richard Farrant]

Thats interesting Richard - your namesake, Richard N. has, I think, a contrary view - I seem to recall him saying on the Stalwart forum over on Yahoo! that he's taken old wheel stations apart that had the additive in and found no sign of wear yet new ones running oil only were already showing signs of pitting etc.

 

 

Hi Neil,

 

Well RN has one Stalwart, whereas working within the REME organisation, myself and colleagues, were doing this on an everyday basis with all types of Alvis 600 series, Daimler Ferret, Fox, etc. We had access to vehicle records so would know the service life of any assembly on a vehicle. Tracta joints would fail even with the additive present.

 

I know RN has cut off wheel stations from scrap Stalwarts, and may have found some in good order, but they may have had a low usage before disposal, or been in reserve, so without service records, no real conclusions can be brought on the use of this additive. I only remarked on the discontinuing of use of OX320, and this was while Stalwart, Saracen, Ferret, and Fox, were still in service.

[ArtistsRifles]

Could also be that the stations in question came from vehicles in private ownership - which likely would have been treated with a lot more respect and acre than would have been the case in active service??

 

It amazes me at time when I stop and think of how much little Maud gets molly-coddled in comparison to the RL's & Militants etc. I drove in service... :-)

[fv1609]

PROBLEM SOLVED! :-D :-D :-D :-D :-D

 

I was going to follow Richard's suggestion of Molyslip (& may still do) but I thought I should remove from the equation, the doubt about the OEP220. Although this was the proper stuff & came from a sealed drum, I thought I should try something else.

 

The very first leakage did occur with EP90 & I have seen many Humbers filled with EP90 not OEP220 that leak through the breather, but I thought lets try with brand new stuff.

 

All I could get from the local garage was Comma gear oil EP80W-90. "EP Gear oil suitable for 80, 85 & 90 applications that require a GL-4 spec." So I put this in, after 5 miles the TF/box has only just hotter than the diff. Where as before it was similar temp after half the distance, but at 5 miles much hotter.

 

After 10 miles there was some leakage but not from the breather. This seemed to be from the drain plug. The aluminium washer has been squashed up quite a few times now & now it was hot I was able to tweak the plug fractionally tighter.

 

After 14 miles no leakage at all. Not scientific I know, but I could put the palm of my hand on the TF/box for a second or two pretty hot but after 12 miles previously it was untouchable.

 

So I don't know whether this particular oil is thinner than OEP220 or the EP90 I had used or whether it has some additional anti frothing properties.

 

Although interesting to know the reason, I shall just use this stuff in the TF/boxes of Humbers in future.

 

So a big thank you for everyone's input. I posted it here rather than the British section as it was interesting to hear if other types of vehicles suffered from this.

 

The downside of these experiments are the hazards of lying on the ground at laybyes where the tarmac has received special treatment from lorry drivers ;-)

[Richard Farrant]

Good news, Clive!

 

Actually, OEP220 is 80w/90,

 

................so there must be a significant difference, between that and 90EP, then.

 

[fv1609]

Good news, Clive!

 

Actually, OEP220 is 80w/90,

 

................so there must be a significant difference, between that and 90EP, then.

 

 

 

But the mystery is what was so wrong with the OEP220 that came out of the sealed drum? Does it go off with time, was it somehow contaminated or does the stuff from Comma have some extra ingredient?

 

I now wonder would it be 'nicer' for the TF/box if it had some Molyslip given that less friction means less heat & I still wonder if it is hotter than Mr Rootes intended?