Believe it or not, I found an old Mercedes thread where a DIYer removed staked-in u-joint, then installed and re-staked a new one. The thread started in 2011 !! The OP reported back into the thread in 2021 (last page) that the u-joint is still working.

And the OP only used simple shop tools, like a Dremel grinder, punches and hammers, and grips.

The "how I did it" starts on Page 3 of the thread, which is below ... I know, folks in here probably wouldn't tackle this job, but it's an interesting read

https://www.peachparts.com/shopforum...what-do-3.html

 

This is what our X204 Output Shaft Housings look like. There is a typical "cross" style U-joint right in the middle of the gear you see here. I had 2 old respected Driveshaft shops just kinda laugh when I brought my original one in to see about a rebuild. Again, one Cannot buy this from MB or any typical MB parts supplier that I ever found.

 

(I hope this thread helps other GLK owners out down the line as there are a lot of noise/vibration threads but the amount of information or follow up is pretty sparse.)

Can someone link any halfway decent front driveshaft / flex disc / center bearing videos/tutorials/DIY's because finding any for the GLK specifically don't seem to exist. Do I remove the whole exhaust? Do I remove the rear tranny brace and lower it with a jack as far as possible to get the rear slip part of the front shaft off because there's no room to slide it forward? There was some site that TALKED about doing it but not HOW to do it and said it was a three hour job; everyone on any forums says its a nightmare and impossible in that time but don't explain why or how they eventually fixed it. I have no issues removing whatever needs to be removed but knowing how to do it the easiest way ahead of time will save a lot of on the fly guesswork and headache, especially since I'm doing this overnight tonight.

Update: I took a look at the flex discs yesterday as well and they looked fine, I didn't notice any cracking or missing pieces at all but I've also read threads where people replaced ones that appeared fine and it fixed their issue. The front driveshaft was supposed to be delivered Friday and I was going to spend the weekend replacing stuff but it was being delivered by FedEx and ... well my hatred for that service is beyond words, it never showed. It's supposed to show today.

It has now developed a clicking noise that speeds up/slows down with driving speed but only from a stop up to 15~mph. I had someone I know that owns an ML tell me they had the same thing happen and replaced their front drive shaft and flex discs and it fixed the issue. That doesn't really narrow anything down to any single specific possible cause though.

I'm not sure if it was that I couldn't get an ideal grip on it or that it being in park instead of neutral made it so that I couldn't move it at all. I could get my hand on it and fingers around it but there really wasn't any play that I could get to happen. I've read a lot of threads or other sites that mention an abundance of 'brown dust' is a tell tale sign of a failing u-joint. I've replaced non-staked u-joints quite a few times before but it was usually after failure.

 

This part will be the last part I try if nothing else works. You mentioned that if there was any forward/backward play in the front driveshaft that that would deduce a failing output shaft u-joint?

 

If there is a lot of play in it and it clunks when shifting reverse to forward it’s worn. I ruined mine being stuck in snow revving and shifting forward - reverse .

 

If this Output Shaft is your problem then there will be up/down side-to-side play (in a 360 deg radius) at the rear portion of the driveshaft, not front/back play. Yes dust visible in the "hole" where T-case U-joint resides is good indication of a bad Output shaft U-joint. The pic you sent was of the Front of the driveshaft. You need to insure no stress on the driveline when checking this "play." Safely chock the wheels and put Trans in neutral, or better yet place vehicle on a lift to get tires off the ground.

 

Ah, ok, this helps, thank you.

What's a good 'tell' if it's the front u-joint going out? I believe the front one is the one everyone says does the most damage as there's no craddle for the shaft and it just takes everything else out with it.

 

Well its the same "tell' really, up/down side-to-side play. Front is easier to see so that helps. You mentioned "clicking" sound as you drove; I had that as well when my T-case Output Shaft U-joint was toast. There should be a boot on the Drive Shaft at the T-case. It may be disintegrated as well.

 

Did you do the repair yourself? Any hints/tips order of tear-down and install that would be helpful?

 

Have the proper tools you will need on hand like a Mercedes trans service kit, (fill port, adapter, and some kind of hand pump) plus a 32 mm 12 point socket, not a 6 point!

Watch all the YouTube videos you possibly can, that’s very helpful to get a visual on all this.

 

What's the 32mm for? Does this all require front axle removal and then some?

 

No front axle removal. 32 mm is for the rear driveshaft flange. Yes, exhaust needs to be partially unbolted, two clamps, just rear of the transfer case. Luckily, these cars have stainless steel exhaust so that is usually pretty easy. But like I said, watch the YouTube videos, there’s at least a dozen that show different people doing this. Some did it laying on their backs in their dark *** garages. That would be a nightmare, but they managed to get it done.

 

A 2011 4Matic would have the 722.9, correct? I'm about to order the t-case ouput shaft from Maktrans and want to make sure I'm getting the correct one. It's also showing an 18 spline and 22 spline, any way to tell before pulling it out which one is in there?

https://maktrans.net/SQGX7229

 

Yes 722.9. You will need the "new style" output shaft which has the opposing flat areas on the splines.

 

Alright, awesome, so it will be the link I sent; that one says "new design 18 splines and 2 blinded splines". Thanks again, man!

 

Front drive shaft (the one going to front wheels) will have some back and forth play. It's actually had to tell because the gear with the U-join (in the pic above) moves. I thought I had play but it was normal. Once you remove the shaft you can if the piece with splines has any play.
Removing front drive shaft is not hard.
Yes, remove tranny support and lower it a bit with a stand.
Remove the cat part of the exhaust (from manifold to the rear part of the exhaust).
You will need new clamp connections for the exhaust because the existing will be rusted and you will have to just brake the bolts.
There are two bolts connecting cat to manifold. You will want an impact with impact extension and socket. Those are sturdy bolts and came out fine.
Then just unplug the O2 sensor.
Then you will have clear access to 4 bolts that attach drive shaft to the front diff. Those bolts are supposed to be one time use.

Clicking noise is weird and can be a number of things. Hopefully a pebble in a tire (or a nail), but I don't recall if that type of clicking went away at 15mph.