Thank you for the reply. It is much appreciated. Your responses sparked further items of inquiry.

Can the existing 4-sided slotted pinion nut be reused? If using the same nut, at least I would be able to mark the position and compare the old position with the new one for an extra level of certainty with the torquing procedure. I've read of people grinding down a socket to make their own 4-slot flange nut.

What is the staking (peening) you are refering to? I went though a Google image search and came up with this possibility,
Attachment 123668
taken from http://www.gearinstalls.com/charles/charles12.jpg

Is this what you are refering to? I do not recall there being a flat edge on my pinion output shaft. I also do not recall there being any of this type of staking on my slotted nut. Do you have a photo of what you are refering to grind off? I am not sure how keep I would be to do grinding inside the small opening of the yoke orifice.

You mentioned to tap with a hammer on the pinion nut [in the direction of untorquing] to remove it. With these nuts secured with >180 nm of torque, will tapping the nut, which is inside the yoke orifice and the striking bar will be at a disadvantaged angle, always have sufficient impulse force to remove it?

If I have the proper 4-sided slot socket, do I need to bother with any of this? I beleive I have located the proper socket for $56 USD.

Once the pinion nut is removed, do I need some kind of puller as noted in the FSM to remove the yoke?

Oh bugger!

Well not really because staking or peening damages the nut - this is a method of physically locking the nut in place.

Yep people with time on their hands sometimes like to make tools!

Here's a picture

http://www.peachparts.com/shopforum/...-shaft-nut.jpg

(Taken from this thread http://www.peachparts.com/shopforum/diesel-discussion/304903-722-118-automatic-transmission-rebuild-monster-diy-3.html)

The method of removing the nut is also given here =>

http://www.peachparts.com/shopforum/2787565-post9.html

(This link goes to post#9)

Well yes you might need a bit of persistence!

If you want the tool then that's quite a low price. The dealer will sell you one for about 150 USD +...

...make sure you get the right one - there are several variations on the same theme including the rear axle wheel bearing version (now that one is worth getting in my opinion because the rear wheel bearing kits are still supplied with 4 slot nuts)

To remove the yoke I did this

http://www.peachparts.com/shopforum/...input-yoke.jpg

(Taken from this thread => http://www.peachparts.com/shopforum/diesel-discussion/344307-w201-differential-refresh-thread.html)

Stretch, thank you for your replies.

I have determined that I can reuse my 4-slot pinion nut one more time. There are two possible locations to stake the nut. Only one of them was used. The other location is 180 degrees away from the current staking position. That is to say, the shaft have two notches on it 180 degrees apart.

I have also decided to postpone this work for several reasons. Topping this list is money. I would need/want to buy a 3-jaw puller, a in-lbs meter, the flange nut socket, and other unforeseen items. Next is that I am not sure if all the grease splatter, which is on the the chassis, e-brake cables, etc. is due to the grease in the driveline centering sleeve (the rubber was bad upon removal), or if the grease is indeed originating from the pinion seal. My 240D is 35 years old, perhaps the quantity of grease is normal for this age vehicle? Perhaps the leak is slow enough not to be an issue. I will monitor the condition and check the fluid level in the diff. I need to get this vehicle back on the road so I can work on my Jeep's very leaky axle seals.

You could indeed peen or stake the other side and in a way it seems like you are saving money. You would, however, have to buy a tool (and say you have found the right one for what was it 50 something USD) instead of a 12 point nut that will cost less than 5 USD (and perhaps a deep 12 point socket for it for say 25 USD)...

...if money is tight I encourage you to look at the whole cost!

There is also the correct slotted socket on eBay for $25. I think it would be tricky to hammer the nut out while the diff. is in the vehicle on jack stands. If I do this job in the future, I'd want to use the proper socket.