W251 R500 transfer case

[Neilof]

Hello, I’m looking for some advice on my currently immobile R500. Whilst driving a couple of weeks ago I heard/felt a loud short rattle from somewhere central. Panic ensued, I found a side road to stop in switched off ignition and read a lot of codes for implausible speed etc. Cleared codes restarted and encountered limited drive as if something in the drive line was slipping, this was accompanied by a whirring sound and some slight vibration. Forward and reverse drive continued to deteriorate to the point when selecting gears, which seem to engage and change on the dash display when cycling through them, results in no drive at all just the whirring sound and vibration, however “P” no longer results in ‘locking’ the gearbox, so it’s held solely on the foot operated park brake. No codes are showing, which I would expect if the gearbox was at fault, but the lack of “P” function is confusing.

For info, in the last 100miles it’s had wheel speed sensor, new battery, all new brake lines, pads and discs and after all of that was running no fine until it wasn’t!

Could it be gearbox or transfer case? If latter does anyone know roughly the labour time to remove? This is one job I’m unwilling to have a go at on the drive.

Car recovered home where it has sat awaiting its fate, likely to be scrapped...

 

[Jobsworth]

There is a hyvo chain inside the transfer box which can stretch and jump. If it fails completely park doesn’t work, so hopefully it’s as simple as that. It’s possible to open the case and replace the chain in situ, but I always take the transfer box out as it’s less messy on the bench. You can’t buy the chain from Mercedes, but you’ll find them online

 

[Neilof]

That's really helpful. I've seen chains online and was going to chance getting one, but I'm a bit apprehensive about removing the transfer case. I've read people have resorted to putting the car in drive and moving to break the connection between drive shafts and transfer case! Any idea how long a transmission specialist would take to remove the case?

 

[W1ghty]

That's really helpful. I've seen chains online and was going to chance getting one, but I'm a bit apprehensive about removing the transfer case. I've read people have resorted to putting the car in drive and moving to break the connection between drive shafts and transfer case! Any idea how long a transmission specialist would take to remove the case?

You aren’t that far from Jobsworth

 

[Neilof]

This is all getting a bit positive! I don't have the necessary post count for PMs though...

 

[Jobsworth]

You can reach me at unclebenz at hotmail dot co dot uk, but it’s for advice only. I don’t trawl the forums for work. I already have more than I can do!!

 

[WilliamParsons]

That's really helpful. I've seen chains online and was going to chance getting one, but I'm a bit apprehensive about removing the transfer case. I've read people have resorted to putting the car in drive and moving to break the connection between drive shafts and transfer case! Any idea how long a transmission specialist would take to remove the case?

I'm glad you found the information helpful. Removing the transfer case can be a complex job, and it typically involves more than just breaking the connection while in drive, as this can lead to further damage. The time it takes for a transmission specialist to remove the transfer case can vary depending on factors like the specific vehicle, its condition, and the expertise of the technician. Generally, it can take several hours to a full day for a trained professional to properly remove and replace a transfer case. It's essential to consult with a specialist for an accurate estimate based on your specific situation.

 

[Jobsworth]

Is Mr Parsons an AI robot? The answers posted seem very peculiar to me. Reading back through past posts they all seem to follow a pattern

 

[W1ghty]

Is Mr Parsons an AI robot? The answers posted seem very peculiar to me. Reading back through past posts they all seem to follow a pattern

I did tell him the other day to remove his nome address details , he hasn’t yet .
Ask him , maybe he is programmed not to lie

 

[Oleks1992]

Yep certainly sounds like chain is stretched in the transfer box, not that hard to do yourself

 

[Neilof]

Just for closure, I sold it on ebay as spares, I just didn't have the time to get into it. A couple of transmission spealists I contacted did say it could be a number of things, which would have taken a fair chunk of cash to accurately diagnose. It did reappear a few months later on I think gumtree, looking like it had been repaired. I replaced it with a 3.5 petrol viano.