How do I put gear oil in the front diff case!??
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Newbie
Joined: Oct 2024
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How do I put gear oil in the front diff case!??
My mechanic says that you have to pull off the front wheel, cv axle and intermediate shaft thereby exposing the pinion seal opening then pour in the oil about 0.65l. This is crazy and costs over $1000. Can you just pump it through the drain hole with a 3 way valve of some sort of rig. What have you tried?????
Member
Joined: Apr 2022
Posts: 148
Likes: 47
From: Tewksbury, MA
2008 S550
Yes, there is no fill hole, only a drain hole. On Amazon, you can get a pump with various attachments to pump the new fluid in after you drain the old. It's a little messy but it works. The pump costs $50-60.
Senior Member
Joined: Apr 2023
Posts: 481
Likes: 306
2014 S63 2010 ML350 Bluetec 2009 SL550
My indy just did this on my w222 and it was exactly as you described. He had some kind of 1 way valve he screwed into the drain hole that he used to pump the fluid back in.
MBWorld Fanatic!
Joined: Sep 2005
Posts: 6,191
Likes: 242
From: Albuquerque
'10 CL550, '12 GL550
My 2007 GL has both drain and fill plugs for both front and rear differentials.
However, it has no published drain interval for changing the fluid.
When I did it at 10 years, 75K miles, the fluid came out appearing brand new.
There is little to no reason for fluid to be contaminated unless the diffs go under water. Motor oil is contaminated by combustion products blowing by piston rings. Nothing similar happens with gearboxes.
The combination of petroleum chemists and mechanical engineers due to their education, testing, and experience have a pretty good idea what's required as regards oil breakdown. Your mechanic is not qualified to advise ... otherwise he'd have more education and a better job.
Recall that maintenance of German cars is expected to be performed by trained professionals who must inspect everything. This is yearly or every 10K miles. If something unusual has occurred to create fluid loss they will find it and advise. CV joints really aren't lifetime components, so when one fails its an opportunity to renew diff oil.
However, it has no published drain interval for changing the fluid.
When I did it at 10 years, 75K miles, the fluid came out appearing brand new.
There is little to no reason for fluid to be contaminated unless the diffs go under water. Motor oil is contaminated by combustion products blowing by piston rings. Nothing similar happens with gearboxes.
The combination of petroleum chemists and mechanical engineers due to their education, testing, and experience have a pretty good idea what's required as regards oil breakdown. Your mechanic is not qualified to advise ... otherwise he'd have more education and a better job.
Recall that maintenance of German cars is expected to be performed by trained professionals who must inspect everything. This is yearly or every 10K miles. If something unusual has occurred to create fluid loss they will find it and advise. CV joints really aren't lifetime components, so when one fails its an opportunity to renew diff oil.
MBWorld Fanatic!
Joined: Feb 2017
Posts: 2,315
Likes: 1,215
From: Baltimore County, MD
'13 s212 63 p30. '06 LX470
My 2007 GL has both drain and fill plugs for both front and rear differentials.
However, it has no published drain interval for changing the fluid.
When I did it at 10 years, 75K miles, the fluid came out appearing brand new.
There is little to no reason for fluid to be contaminated unless the diffs go under water. Motor oil is contaminated by combustion products blowing by piston rings. Nothing similar happens with gearboxes.
The combination of petroleum chemists and mechanical engineers due to their education, testing, and experience have a pretty good idea what's required as regards oil breakdown. Your mechanic is not qualified to advise ... otherwise he'd have more education and a better job.
Recall that maintenance of German cars is expected to be performed by trained professionals who must inspect everything. This is yearly or every 10K miles. If something unusual has occurred to create fluid loss they will find it and advise. CV joints really aren't lifetime components, so when one fails its an opportunity to renew diff oil.
However, it has no published drain interval for changing the fluid.
When I did it at 10 years, 75K miles, the fluid came out appearing brand new.
There is little to no reason for fluid to be contaminated unless the diffs go under water. Motor oil is contaminated by combustion products blowing by piston rings. Nothing similar happens with gearboxes.
The combination of petroleum chemists and mechanical engineers due to their education, testing, and experience have a pretty good idea what's required as regards oil breakdown. Your mechanic is not qualified to advise ... otherwise he'd have more education and a better job.
Recall that maintenance of German cars is expected to be performed by trained professionals who must inspect everything. This is yearly or every 10K miles. If something unusual has occurred to create fluid loss they will find it and advise. CV joints really aren't lifetime components, so when one fails its an opportunity to renew diff oil.
MBWorld Fanatic!
Joined: Oct 2019
Posts: 5,156
Likes: 1,770
From: Colorado
G550
My understanding about gearbox fluids is that contamination is not the problem, but break-down due to temperature and shear stress is, especially if you tow regularly. So the fluid can appear "new" but its lubrication properties after 75K miles are worn. I'm not a chemist -- I just follow the car's maintenance schedule. A couple quarts and an hour's work is not worth over-thinking it.
Junior Member
Joined: Sep 2022
Posts: 67
Likes: 31
2011 S550 4matic
So I just had the intermediate shaft bearing go bad. I decided this would be a good time to make sure no junk in front differential. I emptied from the drain plug. You really don't need anything special. The 10 dollar hand pump from any auto parts store has a 3/8 tube that fits snugly in the drain hole. Just refill from there. As for the oil, that's not a local item, need liqui moly 85w90 gl5. Its about 10 dollars a quart plus shipping. I guess you could sub 80w90 gl5 that is available everywhere but I stuck with the 85w90 spec.I know they say this is permanently filled but at 200k miles, what I got out of it wasn't the capacity .6 litres, more like .3 or .4 so Im glad I serviced
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Junior Member
Joined: Jan 2025
Posts: 21
Likes: 8
w164 ml350
My 2007 GL has both drain and fill plugs for both front and rear differentials.
However, it has no published drain interval for changing the fluid.
When I did it at 10 years, 75K miles, the fluid came out appearing brand new.
There is little to no reason for fluid to be contaminated unless the diffs go under water. Motor oil is contaminated by combustion products blowing by piston rings. Nothing similar happens with gearboxes.
The combination of petroleum chemists and mechanical engineers due to their education, testing, and experience have a pretty good idea what's required as regards oil breakdown. Your mechanic is not qualified to advise ... otherwise he'd have more education and a better job.
Recall that maintenance of German cars is expected to be performed by trained professionals who must inspect everything. This is yearly or every 10K miles. If something unusual has occurred to create fluid loss they will find it and advise. CV joints really aren't lifetime components, so when one fails its an opportunity to renew diff oil.
However, it has no published drain interval for changing the fluid.
When I did it at 10 years, 75K miles, the fluid came out appearing brand new.
There is little to no reason for fluid to be contaminated unless the diffs go under water. Motor oil is contaminated by combustion products blowing by piston rings. Nothing similar happens with gearboxes.
The combination of petroleum chemists and mechanical engineers due to their education, testing, and experience have a pretty good idea what's required as regards oil breakdown. Your mechanic is not qualified to advise ... otherwise he'd have more education and a better job.
Recall that maintenance of German cars is expected to be performed by trained professionals who must inspect everything. This is yearly or every 10K miles. If something unusual has occurred to create fluid loss they will find it and advise. CV joints really aren't lifetime components, so when one fails its an opportunity to renew diff oil.
I was into BMWs when they changed from a defined interval to lifetime fill, the fluid didn't change spec. There is an old school bmw Maintenance document from roundel that the author explicitly states isn't his schedule but just the old bmw schedule. I assume the same thing happened at mercedes and was accelerated when maintenance was included with purchase.
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MBWorld Fanatic!
Joined: Feb 2012
Posts: 2,641
Likes: 1,224
From: Phoenix
222 S-65
My 2007 GL has both drain and fill plugs for both front and rear differentials.
However, it has no published drain interval for changing the fluid.
When I did it at 10 years, 75K miles, the fluid came out appearing brand new.
There is little to no reason for fluid to be contaminated unless the diffs go under water. Motor oil is contaminated by combustion products blowing by piston rings. Nothing similar happens with gearboxes.
The combination of petroleum chemists and mechanical engineers due to their education, testing, and experience have a pretty good idea what's required as regards oil breakdown. Your mechanic is not qualified to advise ... otherwise he'd have more education and a better job.
Recall that maintenance of German cars is expected to be performed by trained professionals who must inspect everything. This is yearly or every 10K miles. If something unusual has occurred to create fluid loss they will find it and advise. CV joints really aren't lifetime components, so when one fails its an opportunity to renew diff oil.
However, it has no published drain interval for changing the fluid.
When I did it at 10 years, 75K miles, the fluid came out appearing brand new.
There is little to no reason for fluid to be contaminated unless the diffs go under water. Motor oil is contaminated by combustion products blowing by piston rings. Nothing similar happens with gearboxes.
The combination of petroleum chemists and mechanical engineers due to their education, testing, and experience have a pretty good idea what's required as regards oil breakdown. Your mechanic is not qualified to advise ... otherwise he'd have more education and a better job.
Recall that maintenance of German cars is expected to be performed by trained professionals who must inspect everything. This is yearly or every 10K miles. If something unusual has occurred to create fluid loss they will find it and advise. CV joints really aren't lifetime components, so when one fails its an opportunity to renew diff oil.
Fluids break down. Coolant, engine oil (10,000 mile interval is fine if you intend to trade it off in 30,000 miles), transmission oil, ABC/MBC, power steering, brake fluid, all gear oils.
Your car, your choice. I choose to renew fluids more often and have never had a transmission, differential, power steering, brake hydraulic, ABC failure that could be blamed on quality of the fluids involved. I sure have seen the results of ‘deferred maintenance’ in clients cars.
Looking down your nose at mechanics doesn’t say anything positive of you.
MBWorld Fanatic!
Joined: Oct 2019
Posts: 5,156
Likes: 1,770
From: Colorado
G550
The combination of petroleum chemists and mechanical engineers due to their education, testing, and experience have a pretty good idea what's required as regards oil breakdown. Your mechanic is not qualified to advise ... otherwise he'd have more education and a better job.
OTOH, my neighbor is a retired (only officially) mechanic, and he's one of the smartest guys I've ever met. His shop is always filled with repair projects ranging from chainsaws to heavy industrial machinery. He can fix it all in the time I'd be trying to figure out which wrench to use. I never hesitate to ask him for advice, despite my "superior education".
