There was a noise of something slipping under load which eventually got worse so that it even slipped under cruise control. I took it to the dealership and got a quote for $11,609.01 for front axle/transfer case repairs. Since the car is only worth about $4500 this would write it off: UNLESS I can remove these components and convert it to rear-wheel drive only. I thought that if I remove the front propeller shaft from the transfer case to the front differential. Then remove the transfer case as well. Next connect the output shaft from the transmission directly to the rear differential. This would make it like hundreds of thousands of Sprinter vans with the same engine.
My ML320 has NEVER been driven hard so I'm very disappointed with Mercedes' design as I feel these components should outlast the life of the car. If anyone has done this or has any positive thoughts on this, their comments will be appreciated.

 

Could this noise be just slippage of the transfer case chain? This would be a relatively simple repair. I found this video that describes the exact problem that I'm having:
I have ordered a new chain, ATF fluid, PERMATEX® GEAR OIL RTV GASKET MAKER, and a stubby 8mm to remove the top bolts on the transfer case.
WATCH for updates.

 

Can't be that hard to pull the front axles and check the splines.

 

The dealer estimate is terrible. None of the numbers add up. Fire them and take the vehicle to another dealer or indy shop.

 

How many miles on the car?

I just had the front shafts out of an 06 ml320 (output seals) cdi with 320,000km and the splines perfect.

agree it could be the chain

if not what about a used transfer case and front diff/axles. Surely a wrecker would not charge too much

 

I looked into used parts but I was concerned that I might be getting somebody else's problem. More importantly, I am very confident that the problem is the chain and I now have all the parts ready to go next weekend:
Permatex 81182 Gasket Maker for gear oil/transfer cases
Shell ATF 134
Filler pump and hose
And, it turns out, I didn't need the 8mm wrench as we used a Cordless Ratchet Wrench with various WOBBLE extensions
Total cost = $109.26 plus my labor.

 

I think the dealership's hands are tied by Mercedes. All they are allowed to do is replace items complete with brand-new Mercedes parts. If the only part is a complete unit, then that's what they have to use. They are not allowed to use third-party components nor are they allowed to open sealed units and repair/replace parts inside.

 

It turns out this repair was trivial


I put the car on a lift, mark the alignment for the driveshaft BEFORE removal then removed the rear driveshaft bolts (Torx T55 bolts), and the tricky part to push the driveshaft out of the way:
Drain the old ATF.

Remove the 12 T10 Torx bolts, plus a bracket holding the DPF sensor (T12 Torx bolts), and then lever open the transfer case with pry bars at the points on the right and left of the case:

Checked splines are OK

Checked bearings are OK
Compare the old, stretched chain with the new one:

Stretched chain on the right
BE CAREFUL—there's a small metal plate which may drop out. After cleaning the mating surfaces, apply Permatex and reinstall by cinching down with several bolts around the case. Finally, torque to 40Nm:

Fill the transfer case with ATF fluid until it comes out of the top filler hole (~500ml), reinstall the plug and bracket. Tighten the rear differential according to the document attached (1 => 10Nm, 2-3-4-1-5-6 to 40Nm, 2-3-4-1-5-6 final to 90Nm [in park with footbrake on and you will need wobble extensions to fit in the space and make the required torque]).
Now, it's all fixed. I am very grateful to Jimmy of Oishii Imports for ALL of his help and the use of his facilities. *****

 

Nice work. Thanks for positing. Others on Youtube have made this look much harder. You didn't want to change the bearings whilst you were there?

 

No need to replace anything but the chain. Bearings, gears, splines were as good as new.

 

Wow, nice job. How much did this job end up costing in comparison to the dealers estimate? What a bunch of fawking clowns the dealers are.

 

The Labwork Gear Transfer Case Chain A2512800900 Fit for Mercedes ML & GL & R Series 2003-On was $61.19
Permatex 81182 Gear Oil RTV Gasket Maker, 3 oz. was $9.98
Plews 55001 Lubrimatic Fluid Quart Pump was $11.32
Shell ATF 134 Mercedes Benz Transmission Fluid 236.14 was $16.24
Total (from Amazon) is $98.73
You don't need the 8mm wrench but I suggest you get a good set of Torx male and female (the T55 might not be included in a set).
The actual transfer case is NOT made by Mercedes it is from Borg-Warner and they have a more expensive chain but I could see no difference from the Labwork one (I wouldn't be surprised if Labwork made the Borg-Warner chain).

 

Jesus fawk! Nic work and kudos! Dealers should go kill themselves.
And this fixed your otherwise 12K problem?

 

This fixed the problem completely. I have full acceleration again with no sign of slippage.

 

Holy crap.

i am shocked and appalled a reputable dealer would try something like that as….well not really who the hell are we kidding here…Nice DIY and tell that dealer to go f themselves.

 

Actually the chain is Borg Warner and the case is made by Magna Styer in Austria.
I wouldn't put anything but USA made Borg Warner chain in the case, every other brand is made in China.
The dealer probably would've changed the chain and sold you a transfer case, pocket the moola.

 

My God. I would leave a terrible review for that dealership.

All the poor people that are being taken advantage of at these dealers. So criminal.

 

Exactly that.
If money is no issue the official dealerships are great.They repair to new state.
For normal human beings it's doing a lot of homework and handywork yourself and/or find a good independent garage who will think with you.

 

Actually, I have had no problems whatsoever with the Chinese-sourced chain. The only problem I had was with the original Borg Warner chain. I'm not sure what you are basing your comment on other than speculation (of which there is way too much on this forum).