just replaced my transfer case- change your fluid!
 

for others with these problems this is what i found with mine

this truck had 78,000 miles on it

i had the same symptoms as another forum member

truck was fine with no noise as long and you did not get on it pretty hard from a standstill

tried to use a remote camera to look inside it but you cannot get past the chain

but we could see by pulling the drain and refill plugs that the chain was very loose

went to a junkyard and got one with 100,000 miles, took it to the differential shop and we opened it to make sure everything was good before i installed it

it looked good inside and the chain was tight

installed it and no more problems

took the other one apart and found the chain was super loose and the snubber bracket was broken just like the other posters pictures

my broken one had a plastic snubber and the new one metal but it does not seem like this has anything to do with it

the bracket that the snubber bolts to breaks, it is a bad, weak design

but my diff guy thinks this is only because the chain is getting stretched out and he thinks this is only because people are not changing the fluid

he recommends changing it every oil change, it is cheap and easy to do so would not be a big deal to do it every 10000 miles

from what i can tell mercedes does not tell people to change it at all

i just bought this truck and the extensive dealer records do not show this had been changed

anyway just wanted to fill people in on my experience , hope it helps someone else

Thanks had not considered that, ive got 60 k on mine i will add that to my normal maintenance

We are just approaching 80k miles on our 2010 GL550, so I am going through the maintenance booklet. It only lists the typical engine oil/filter change and to have the transmission service (fluid and filter).


I typically take the GL to the local "oil change" shop. Would they know what to do for you are specifying? Why wouldn't the maintenance manual mention this, I wonder?

i have no idea why mercedes does not list the transfer case, my guess is they want us to buy transfer cases instead of changing fluid

i dont think the front and rear diff fluids are listed either, or maybe not until 100,000

all this stuff is so cheap to me it is crazy not to do it

and there are too many posts about transfer case and front diff problems to take the chance

changing the transfer case fluid is very, very easy
it requires mercedes transmission fluid, half a quart for non off road option
think the off road option needs more

word of caution
my mechanic commented on the fact he thought front diffs were not getting properly refilled and were low, that this might be contributing to the problems on the ml and gl

the transfer case fluid has to be pumped back in so this also might be where it might not get filled to the right level

i would make sure they do it correctly

and imo you could find a good mercedes indie mechanic to do these changes for the same price or just a little more and be safer on all of it

especially if you are going to have the trans done too

Just changed the front and rear diff fluid at 60k and it was black, no metal but you can tell the fluid is breaking down. appears to be heat related as it is over 100 here in the summer and im hard on it. By all the cooling fins on them you can tell mercedes was concerned about heat. Funny ive never seen this condition on my Avalanche or my Jeep with no fins but they hold a lot more fluid which is probably why.
Went back with the genuine fluid as i couldnt determine exactly what was special about it other than its lower viscosity which is really noticeable.
So glad i changed it. Lifetime fluid....

Only half a quart?

my manual says .5 quart mercedes trans fluid
my truck is 2008 gl320

transfer case double speed -which i guess is the off road package - says 1.6 quart

maybe this is why the chain is stretching out and several people had transfer case issues, because there is so little fluid in them.....

at any rate it is cheap and easy to change

Half a quart? If it leaked even a little bit it would be gone.

I'm used to my '96 Land Rover, it's been marking the driveway for years.

Thank you for the info clvincent

It seems like the diesel engine models are the ones suffering this type of failure. I'd bet it's associated with towing.

I am not sure that i agree with towing being the issue, mercedes seems to have
Problems with transfer cases across the board even in the cars

Towing not an issue. plus I don't have a diesel and my transfer case went bad. And I never tow with my gl450

Just changed engine oil on my GL this Saturday. Next service will do the diffs and transfer case. I dont believe in lifetime fluids myself.

So transfer case fluid is transmission fluid? What about the diffs? Any DIYs on it? I am sure I can figure out the rear diff but wondering about front and t-case.

t case is super easy, and easy to get to both bolts

i dont remember what my mechanic did on the front diff but think it takes him 10-15 min to do it, so must be easy
i am running royal purple in both diffs, it is hard to find the exact weight for it- RP does make that weight but no one around me seems to carry it

but my mechanic and diff said whatever the common weight i found was ok...

Have you owned since new? Does it have a tow package on the vehicle?

I did both diffs and the transfer case on my 2012 GL350 this weekend while I was doing the 50,000 mile oil service. The job is easy and probably took 25 minutes for all three, though access to the fill hole on the transfer case is annoying as you have to route the fill tube over the obstruction. The transfer case fluid was filthy so I'm going to move the change interval up to 20,000 miles. The rear diff is annoying too as it is blocked by the exhaust (I had to use a Allen key and now I'm definitely ordering those low profile Allen sockets I've been eyeing). After staring at it it's dawned on me that the dual exhausts on this car are completely superfluous and that a single exhaust would have allowed them to design the DEF tank differently and fit a spare tire in there. Hans and Franz seem more concerned with fashion than practicality.

Here's photos:

Front Differential:

https://cimg4.ibsrv.net/gimg/www.mbw...257abb72e2.jpg

Rear Differential:


https://cimg8.ibsrv.net/gimg/www.mbw...89feb9a0d7.jpg

Transfer Case:


https://cimg0.ibsrv.net/gimg/www.mbw...cfaed01ffd.jpg

any instructions how to DIY? :-) parts etcc..?

thanks

Sure, this is about as easy as it gets. The two diffs use a gear oil, though MB states that they are both slightly different weights and neither one of those weights are commonly available. I used Mobil 1 Synthetic 75 W 90 in both; if it's good enough for the diff in my race car, it's good enough in a GL that doesn't see a fraction of the stress. It's worth mentioning that when you choose your fluid, keep in mind that these are limited slip differentials (LSD) and require a friction modifier to keep the LSD discs happy. Mobil 1 contains a friction modifier but some others may not (Red Line, for instance sells both with and without.) A quick learning opportunity: with a vehicle raised, you can tell if it has an LSD by turning one of the wheels. If the other wheel turns in the opposite direction, you have LSD. If it moves in the same direction, you don't.

For the transfer case, you use MB ATF 134 (the red color, but check to make sure.) It's about $20/Liter from the dealer and you only need 1/2 quart.

Here's the steps, same technique applies to all.

1. Drive the vehicle a few miles to heat up the fluids to make them flow better, then pull it into your work area. Raise the vehicle on stands (or if you are really skinny, just shuffle under there); it should be on a level surface, or with the nose slightly down at worst; if the rear end is lower you won't be able to fill enough fluid in and this is especially bad for the transfer case which only holds 1/2 L.

2. Use an 8mm Allen socket to loosen the drain (i.e. the top) bolt first (a couple of the plugs required an actual Allen key - the 'L' shaped kind, due to clearance issues with my socket so you might want to have both on hand.) This should be obvious because if you drain the fluid then can't get the fill bolt loose, you are in trouble.

3. Get a catch pan, and loosen the drain (i.e. lower) bolt, and let the fluid drain into the pan. The diffs will drain a bit more slowly than the ATF in the transfer case, so you may want to raise up the pan closer to the drain plug so that you don't make a mess. Gear oil is some smelly, nasty stuff.

4. Now that the fluid has drained, replace the drain plug and tighten (I don't know the torque spec, maybe somebody can confirm; I just do it to feel.) The diffs use o-rings on them, but the transfer case does use a 16mm copper crush washer; you can source these from many sources or get them from the dealer; you need to replace it with a new one. Now take a fluid transfer pump and insert the exit hose into the fill hole. This is what a fluid transfer pump looks like; available at any auto parts store:

https://cimg7.ibsrv.net/gimg/www.mbw...279744aecb.jpg

Pump the fluid in until it starts to weep out around your fill tube, then quickly screw in the fill plug. Approximate volumes are 1 1/3 L for the diffs and 1/2 L for the transfer case.

5. Tighten down the fill plug and you're done. Lower the car and crack open a beer.

It is a pretty easy job. Clearance on the rear diff drain bolt is the only complication. I couldn't get the socket + ratchet in the available space between the diff and exhaust, but i could get just the socket in, so I put a 8mm closed end wrench on it before putting the socket into the bolt and used the wrench to turn it. The fluid on all of mine looked amazingly clear for fluid that has never been changed (other than maybe the xfer case fluid when the trans was out?) in 150K miles.

since new and I do have a tow package. I use my z71 suburban to tow

nice I will do this when it gets warm outside :-)

thank you for the DIY

Something to think about if you're replacing transfer case fluid....

Apparently yes the correct level is 0.5L (half a quart approximately). But some have said that this is NOT enough fluid for the system and it runs partially dry. I'm sure with a few minor leaks over time you don't have great lubrication inside the unit.

It was said that 0.7 to 0.8L is a much better level. You can apparently not easily overfill these things and it wouldn't do too much damage unless way overfilled (ie. 1.0 liter or more)

I had my transfer case changed and new fluid put in. But next time I am changing the fluid myself, I'll be putting in 0.75L

Just something to think about if you're doing the job...

Marked

Good info, if the left side of this picture is the rear of the vehicle, putting the rear lower than the front would raise the fill hole allowing extra fluid to be added. One could change the differential fluids on level ground then adjust the tilt of the vehicle to get a little more transfer case fluid in. Similarly if you only raised the front passenger corner of the vehicle it should raise the fill hole and allow more fluid. Of course this assumes I'm looking at your picture correctly.

Actually, that picture is taken looking forward so the drain hole is on the left and the fill hole is on the right. The only way to get more than 0.5L into this thing would be to raise the rear of vehicle significantly more than the front, or to raise the right side significantly more than the left. That's because as soon as you pull the fill tube out, the relatively thin ATF starts pouring right back out of the fill hole.