[Joe-V12]

Here's mine out of a ~135k mile S420 with complete failure from K2 bushing bearing, so I can vouch for the ATSG guide info. As K2 bushing bearing wears it allows misalignment of the input and output shafts, so the speed sensors end up getting rubbed by the windows. If your transmission has never been rebuilt with updated parts I'd seriously consider it. The pic is not a close up but you get the idea of what is going on.

 

[Joe-V12]

Mine gave no warning. I even serviced mine and dropped the pan which showed nothing to worry about but I did not drop the valvebody and conductor plate.

If you end up with bearing rollers going through your planetaries, and you will know if it happens, drive in 4th and don't stop until you reach home. In 4th gear damage in minimised as all gears are locked 1:1. Other possibilities are slippage or wiped out speed sensors that will put you in limp mode.

If you want to preserve K2 bearing bushing as much as you can drive with the shifter in 4th and avoid time the transmission in N to minimise movement on the K2 bush surfaces.

Are they metal particles in the cracks on that speed sensor drum?

 

[Joe-V12]

Hi Joe,


When you mention "avoid time with the transmission in N" does that also include P? (it's a locked N after all)

yep

 

[Joe-V12]

Mine is being rebuilt as we speak, but since my car is a Diesel, I always let it idle a few minutes when starting cold.

Yeah after leaning about these transmissions I was letting the 600 warm up in D before taking off. Of course normal use sees many many years of life.

If you have a suspicion your transmission is on it's last legs, or want to give it the best chance at a long life then avoid N and P with the engine running, and leave the shifter in 4th for driving.

It all comes down to how proactive and paranoid you want to be.

 

[Joe-V12]

Speed sensors on a W220 S500 722.633 with no physical damage or wear on K2 needle bearing. Mileage unknown:

 

[Joe-V12]

Yep, cracked, so they can just crack from age/use without the K2 problems having any effect.

 

[Joe-V12]

Dan O, pics of the scuffing might help a free remote diagnostics.