D47u Final Drive Over-filled?

i don't think u can blow those seals like u can roller seals. the fluid seeks level and u probably did overfill. i understand they may take a bit to seal. i think cat makes a big expensine wrench to tighten them up after running awhile if still leaking, i believe.

Hi James,
as you know these seals are a cork facing on the bellows. The facing is set at an angle of 3 Degrees so that contact occurs at the outer edge of the facing. At the Dealer we always lightly sanded the facing on a sheet of emery paper on the surface table to get at least 1/16" witness mark around the outer perimeter of the facing for a positive sealing and ensure there were no dents in this area to cause leakage.
ag-mike has correctly stated that these seals, if not faced as described, take a while to wear/seat in, so I would operate it at present and keep an eye on the oil level in the F/D and the leakage rate should diminish.
Hope this helps.
Cheers,
Eddie B.

If you think the reason is over filling, put the critter on flat ground and remove the fill plugs, NOT the drain plugs. Any overage will run out so have a drain pan under each one before you pull the plugs.

Thanks Men! Based on your advice, I think we did over-fill the final drive.
ol' Grump, when we leveled the machine and opened the fill plugs, it did puke oil for a while.
edb, the Dealer parts man nor the mechanics ever mentioned lightly sanding the facing on a sheet of emery cloth. In fact, the service manager advised me to pump grease in the final drive instead of repairing it, since the machine was so old (1955)! Maybe next time...

The D4 7U doesn't have breathers for the final drives, which exacerbates the overfill problem. There is a breather on the transmission, but none for the final drives.

There isn't a huge volume of air space in the top of the 7U final drive housing, so an overfill would reduce that air space to a relatively small amount.
Once you start operating the tractor, the gear action generates some degree of pressure via the thrashing of the oil (when the final drive warms considerably, the problem increases).
If you've ever part filled a small container with warm water when washing, then placed the lid on, and shook it up .. then unscrewed the lid .. you were probably surprised at the pressure generated by the shaking. The final drive on the 7U is not much different. Maybe the final doesn't get the same violent shaking as you'd give a container .. but it gets a pressure build-up, regardless. That pressure has only one way out .. via the sprocket seal.

The later model and bigger Cats had final drive breathers, that mounted on the top of the rear housing, next to the steering clutch compartment covers, and which had tubes running from the final drives, through the steering clutch compartment, to the breathers, to vent them.
These breathers could get blocked with mud or dirt buildup, and you could end up with pressurised final drive housings. Regular cleaning of the top of the steering clutch housing is necessary with these tractors.

Don't come down too hard on the Service Manager, he's probably never seen or worked on a Cat older than 25 years .. or received training on old Cat drivetrain construction and repair. Cat and their dealers are geared to producing and maintaining new or near-new equipment, for construction, mining and industry .. and Cats 40, 50 or 60 years old are merely historic curiosities to them.
My nephew runs 25 near-new Cats and is only interested in the latest models at all times. He thinks we're all a bit nuts to be interested in running and fixing old Cats, that he thinks belongs in museums .. and maybe we are .. 😄

Hi, OzDozer.
But it's a pretty nice 'nuts', isn't it, especially for those of us who are infected and can understand and enjoy it? He's the one who is missing out. LOL.

Hi, James Hayes.
You have been given the 'good oil' above by some pretty qualified people, some qualified by training and others by doing but all qualified.

I have my own thoughts on the service manager's idea of filling the finals with grease and they are not positive. Grease does not circulate like the gear oil that these finals were designed to run with and can leave both bearings and gears short of lubrication, especially when cold or in colder weather. A semi-fluid chassis grease like the (VERY) old Marfak OO might work for a while but it would still eventually cake up and hang to the sides of the housing and the gears, leaving the bearings and gears short of lubricant. Stiffer greases would be worse.

Just my 0.02.

OzDozer,
If I pressurized the Final Drives, and the pressure had only one way out... through the sprocket seal... Would you think I significantly damaged the seals?

Thanks!

OzDozer,
If I pressurized the Final Drives, and the pressure had only one way out... through the sprocket seal... Would you think I significantly damaged the seals?

Thanks!

[quote="James Hayes"]OzDozer,
If I pressurized the Final Drives, and the pressure had only one way out... through the sprocket seal... Would you think I significantly damaged the seals?

Thanks![/quote]James - No, leakage created by overfill wouldn't damage the seals. The major and regular cause of seal damage is wire or twine wrapped around them.
If you're dozing, and you see even the smallest piece of wire or twine caught in the tracks .. stop, jump off, and hit the wire with a hammer against the pads, cutting it .. so you can pull it out.
Leaving ANY wire caught in the tracks while you're working, is generally a guaranteed way of it ending up wrapped around the sprocket seals. If you stop and remove it, the instant you see it, you won't have any problems. This instruction was drummed into me with great regularity, from the first day I stepped onto a dozer at age 15.