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Differential level

Went to check my differential lubricant level, and the oil gushed out. Manual says only a small amount goes to the axles. It hasn't been driven in weeks. You don't suppose some service guy would have been adding it through the vent tube opening do you?
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Differential level

Reply #1 –
Quote from: Old phart phred –
You don't suppose some service guy would have been adding it through the vent tube opening do you?

OPP,

It wouldn't surprise me the least. Also it is a remote possibility that water has gotten in the vent and the gear lube is setting on top of the oil.  If this was the case the gear oil would be milky if it had been there any time at all and the oil has been agitated.

Pamela & Mike


Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Differential level

Reply #2 –
Have not located the vent yet, clear oil, no evidence of it being in a flood on the coach anywhere. Looks like the carrier may have been changed, cause it's not painted, and silicone at the seam. Nothing in the service records, about it being changed.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Differential level

Reply #3 –
If you are setting level it was most likely overfilled. This is one place that don't make oil from another component leaking into the differential.  On our GMC the trans. and diff. is bolted together and if the right circumstances happen the 2 will share oil which isn't good.

Pamela & Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Differential level

Reply #4 –
Found the breather and it had an oil spill below it that had attracted dirt. Will loosen drain plug in the morning to see if any water come out. My guess is that water would milk up hypoid for quite some time.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Differential level

Reply #5 –
Many differentials used in Foretravels have TWO "fill" plugs.  Correct one depends on angle of installation.  So, absolutely check for your axle model number to make sure which hole is the correct fill level.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Differential level

Reply #6 –
Dana/Spicer J175. Appears to have only one fill hole slightly lower than the Centerline of the axle. Is there another one on the carrier side?
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Differential level

Reply #7 –
They don't have one on the carrier side, but a lot of times there are 2 on the rear one for filling and a lower one for temp sensor.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Differential level

Reply #8 –
Sensor hole is tiny and plugged
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Differential level

Reply #9 –
Pretty obvious, but if it drains clean just lower the level. No need to change.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Differential level

Reply #10 –
If the coach hasn't been driven in a while, I would not drain diff'l oil until it had been driven for a while-20mi.?  You want the wheel bearings to have adequate oil.  It will drain back over time.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Differential level

Reply #11 –
Quote from: amos.harrison –
If the coach hasn't been driven in a while, I would not drain diff'l oil until it had been driven for a while-20mi.?  You want the wheel bearings to have adequate oil.  It will drain back over time.
Incase there is water in it you would not drive it, the water will settle to the bottom. See the first post.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Differential level

Reply #12 –
You probably did this already but make sure the coach isn't leaning to the fill hole side.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Differential level

Reply #13 –
My book says to fill the axle ends separately.  I fill my diff by pulling the  axle, from the end.  With  one side of the axle  jacked up about 1in . The oil gets to the ends  when turning  , but Imake sure it starts with some in the end bearings.  My fillplug is under the axle  bearing  level by about 1in or maybe a little more.
 My full level is about 1/2 in over the plug  when I let it down  . Then I put the axle back in .
    I dont know what has happened in the 30 yrs of this bus and I dont trust the  fill plug to lube the axle ends , being so low .

Re: Differential level

Reply #14 –
I have to pull my axles and hubs to do the brakes on my crane it has the same type rearend. There is always oil in the hub and I have over 600,000 mi. on it now. I fill to the threads on the fill hole. Axle bearings are original the carrier bearings were replaced when I did a gear change. If axle bearings were to be replaced, I would dip them in oil before installing. I have to be careful not to leave any oil on driveways when I do a lift so I wouldn't want any oil dripping from the vent from over filling.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Differential level

Reply #15 –
Pulled the drain plug, and let about a pint out into a clean pan, no water or metal bits. Drained almost 2 Folgers 34 ounce coffee tubs full of hypoid out the fill hole. Between the eruption when I pulled fill plug yesterday, and not expecting anything to come out, and todays procedure, I've probably got a quart on the driveway to clean up. I can only guess someone filled to the breather hole. Previous owner did no mechanical work himself, and relied on a RV service facility.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Differential level

Reply #16 –
With all that gear oil it was probably running much hotter than it should. At least you know your axle seals are good.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Differential level

Reply #17 –
Quote from: Protech Racing –
  I dont know what has happened in the 30 yrs of this bus and I dont trust the  fill plug to lube the axle ends , being so low .

Millions of trucks on the road running millions of miles. Do you think they use your method, or just fill to the bottom of the plug?
1998 U270 34'

Re: Differential level

Reply #18 –
Please post a link to other than "fill plug" fluid level for a rear axle.

Again, some axles have TWO fill plugs depending on angle of installation.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Differential level

Reply #19 –
Quote from: krush –
Millions of trucks on the road running millions of miles. Do you think they use your method, or just fill to the bottom of the plug?
I full to bottom plug drive around turn left right a couple times, recheck too off if needed, shoot for the moon. Recheck next oil change
91 GV U300 Unihome 40' Build 3811
6V92TA Detroit

Re: Differential level

Reply #20 –
Quote from: stump –
I full to bottom plug drive around turn left right a couple times, recheck too off if needed, shoot for the moon. Recheck next oil change

I like that method.  Some like to over-analyze.  Which is fine, as it is their equipment.

But let's look at this with practical eyes. Have any of ya'll seen inside a gear case, or rear end when the gears are moving?  Oil is flung EVEYWHERE!  I'd bet a lot of money that there are thousands of rear-ends riding around the roads that are significantly low on oil.  Yet, no damage is being done to the bearings or gears.  As long as enough oil is in the sump to get flung around, components are probably going to get proper lubrication.

Roller bearings (anti-friction bearings) require very little oil to keep from failing.  I haven't installed windows on any rear ends, but I'd guess that the oil splashing around also dribbles down the spinning axles to the hub bearings.

Another bit of anecdotal evidence: when rear axles are removed for towing, and cardboard is bolted over the hole, we don't see hub bearing failures.  I've seen brand new trucks being towed thousands of miles from the factory with axles removed and nothing but cardboard covers bolted in place. No bearing failures.  I guess there's enough oil in the hub to keep it all lubed.
1998 U270 34'

Re: Differential level

Reply #21 –
  I'm sure you guys are correct .  I have serviced vehicles  for 40 yrs and this one is the only diff with the fill level substantially lower than the axle tube.  Knowing several vehicles with fill levels different then the fillplugs, I simple went with known good value. At the axle tube. 
 When I serviced the brakes, diff etc. i realized that when you change the diff oil, you do not also change the axle bearing oils.  The hubs need to get removed and tipped on end to get the old oil out.  I would much prefer a weepy axle or pinion seal than an axle/wheel  bearing failure. . The diff noise seems to have reduced also .
 Thanks . MM