We're preparing to move into a new project and so I asked that we get to checking out and making up a repair list for the equipment we'll be taking with us to get going on the job. We found that our old D8H (46A27403) was low on transmission oil. At first, I thought no big deal, we'll top it off and move ahead. My foreman who's in his early 60's calls and tells me I have bigger issues on my hands with this old style 8. He goes through the particulars of what he used to see when he was coming up running these older 8's & 9's and when they started losing oil in the transmission it was usually going to the finals through the bevel gear case and steering clutches. He said typically it was because a seal had failed and oil could move about freely in the compartments. He pulled the plugs on the finals and sure enough they were over full to the point of it pouring out when the top was removed. From what I see there is no way to fix this beyond pulling the transmission and replacing the seal which is, based on reading through my maintenance manual, a big job. He said some companies he worked for pushed ahead and went until the oil pushed out the seals on the finals and some fixed it on the spot. Does this amount to a down the machine issue and is the seal in the picture attached here the one that has failed? Can we safely run the machine and just drain excess oil off a few times a week as we go to prevent the seals from pushing out? For what it's worth, this is a good machine. I pushed some 621's with it while we were short staffed last summer and it was really a pleasure to run. It still has enough push left in her to get the pans in and through the cut just fine.
Its your final drive pinion seals that are overfilling you finals . you have to pull steering clutches and pinon flanges to get to those seals . these dozers have run before with the finals overfull . I wouldnt worry with draining .
When you do replace those seals its a good time to give those steering clutches and brakes a measurment and see what the teeth on those pinion shaft look like
I’ll second what Hatchquip says
Work her on flat ground and less oil will pass from the bevel gear compartment into a final. For future reference, oil passes freely between the transmission and bevel gear compartment. Neither is sealed from the other. How much oil erupted out of each final fill plug. It should be equivalent to the amount of oil decrease on your transmission oil stick. If not, you have a leak somewhere else. Unless you no longer have any seal between the finals and bevel gear compartment, you should be able to finish 2022 with the leaks.
Your s/n range should have duo-cone seals for the upper pinions instead of the lip seals like the older machines. Usually they last better than the lip seals unless the upper pinion or cross shaft bearings are starting to fail. I would pull the trans filter and both final drive filters and check for any bearing flakes or filings and evaluate from there
The oil transfer from the Main Case into the F/Drive compartment can be caused by a few ways, often people blame the top pinion seals but I have taken many to bits and found the Duo-Cone or earlier style seals to be failed without any sign of over filled F/Drives, a good thing to do is checking the breathers to all compartments, I would not loose a jot of sleep over this issue just carry on working them until they are due new Brake Bands or related service repair, it's not going to hurt anything and the chances are it could well be a weld crack or breather pipe damaged. tctractors
Yes,those bevel cases fill up with dust and block the breathers under the diesal thank.Then they get wet,then more dust builds up and before you know it,the breathers are buried under a ton of crud
Give or take 2 gallons a side. We put 5 gallons in the transmission and just barely got it on the stick.
I am going so send our mechanic by with some information from the service manual to check these breather out and clean or replace them as needed. Maybe we can get by until she's due for more work on the internals or retirement....
Were going to pull the covers and check this out. Maybe this is part of the issue. Breathers are blocked up and letting the heat buildup make pressure in the case.
It won’t hurt,but most likely the pinion seals have hardened off.Don’t worry about that.If those cross shaft bearings are failing,I think you’d have problems steering etc. It’s allways a gamble,but one I’ve taken and got away with on probably all my D8’s