I pulled a remanufactured AL117X alternator from an 85 300D to replace the one on my 300TD. When I got the alt off of the 300TD, it had a little plastic box screwed onto the back with a socket connector plugged into the tab right next to the 'D' inscribed by the plug.

The one I pulled from the 300D didn't have it.

What is it and do I need it?


I am going to take both to a McParts place tomorrow and have them both bench tested, but I want to know what I am working with first.

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Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

I have often wondered the same thing, im glad im not the only one. Some have those little boxes and some do not.

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1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg

I believe it has to do with electrical noise supression that would be picked up buy your Radio.
It may be the Alternator was made for a Gasoline Engine model.

However, why bother removing it.

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84 300D, 82 Volvo 244Gl Diesel

Probably just a filter for electrical noise.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Which one though? Both are reman., so either one could be the gas model

Its more a matter of do I bother moving it to the new one....

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Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

I am guessing that the Black Box one is made for the Gasser because the Gasser has more electrical stuff on it to make a larger volume of Electronic Noise. But, it is just speculation.

If you owned an auto parts place you could see the advantage of stocking one Alternator that would cover Gasser and Diesel instead of stocking 2 different Alternators.
Other parts companies might not mind stocking both types of Alternator. Not having a noise supressor on it might gain them a little more profit.

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84 300D, 82 Volvo 244Gl Diesel

Your speculation is correct since gasser's have an ignition coil which is a big elec noise generator.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

NO... that is not what it is..
it is the same as a black box on an airplane...
it means the Government is watching you and will know when you have an accident how fast you were going and who you were talking to or texting on your phone....
Carefully remove it at night and place it on your neighbor's car... or riding lawnmower.

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

And, Fuel Injection.

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84 300D, 82 Volvo 244Gl Diesel

So close - but no cigar!

It isn't the government it's the Germans. Need proof? It is on a Bosch alternator - made in Germany... take it from someone who lives next door to them.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Noise suppression i.e. radio interference. always remove from old and reinstall in new/rebuilt as they do not come with new/rebuilt units -just did mine a month ago and did the swap

You must understand that mentioning this puts you on THE list right?
attempting to remove the box or warn others to remove it will target you and cause serious problems with your life and your car.
you have been warned

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I am nursing an injured knee.. must have been the drugs typing... I guess there is no escaping THE list...

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

What is it with you guys over there?
Are you all weak kneed?
First TW & now you!!! Maybe we need to start a forum for those with a weak knee !!!!!
Now if it were dodgy backs you could blame it on virility !!

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

Would you believe I hurt it while carrying a 240 block into the garage to clean it up ?
Weakness shows up in the knees just prior to it showing up in the brain...

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html