I just bought a 300TD with the 5-cyl turbo. The car was sold to me as a 1984. I am a bit puzzled, however, as the car has that blue transmission vacuum amplifier unit which I thought was only included starting in 1985. Now, because the car has been repainted, there is no door sticker . The Russian site lists it as (approx.) 1984 based on the VIN. Is there another way to tell what year this thing is?

What I am really interested in is the rear diff ratio. As far as I know, the -85 model year had the 2,88 and the rest had the 3,07. But, of course, in my case, there is no marking on the rear diff. The reason why I am interested is that my car shows speed incorrectly: when the needle shows 50 mph (81 km/h), the real speed is 46( 74 km/h).

So... What I am trying to get to is, if the car is in fact a 1985, then maybe somebody has swapped the 2,88 for the 3,07. The instrument cluster itself looks to be pretty "virgin" BUT has no tach ?!?! Could it be from a non-turbo?

I am puzzled...Any ideas?

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1983 300SD, 1999 200 cdi and 1998 1,6 (gasser)

My turbo '81 300TD has no tach.

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Brad
1981 300TD - daily driver
1963 Chevy II
2001 F-250 7.3 Power Stroke

Where is the sensor that measures speed on these cars? I just assumed it was somewhere close to the wheels, but it sounds like that's not the case if a rear end change could affect the speedometer reading.

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" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles

I think its on the tail shaft of the transmission.

Shoot...I was going to ask if you had a tach amp or not , that's usually a tell tale. I think there's also some difference with the way the EGR valve is controlled.

Is it a european model? Does it have little bumpers and other oddities beside no tach?

My speedometer is off as well...probably about as much as what you're indicating. When my speedo reads 75, I'm really going 66-67. So going 46 and reading 50 wouldn't be out of the question..at least on mine.

If I really had to figure out the rear end ratio on mine, I'd lift the back end, rotate the drive shaft once and measure how far the rear wheels rotate. Actually, it'd be better to lock one wheel and measure how far the other one spins, then divide by two. It wouldn't be too hard with a plumb bob and a tape measure (to accurately measure the tire circumference).

The most direct way, though, is to count the teeth on the gears

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1985 300TD-euro 352,000 mi
1974 240D (1?)52,000 mi - has a new home now

On the 124 wagons it comes from the rear differential. Not sure if that's the case with the 123, but it could be.

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1987 300TD 309, xxx 2.8.2014 10,000 mile OCI


Be careful of the toes you step on today, as they may be connected to the ass you have to kiss tomorrow. anonymous

“Be who you are and say what you feel, because those who mind don’t matter, and those who matter won’t mind.” Dr. Seuss

Isn't there some kind of device that will compensate for changes like this to give you the correct speed? It seems like I remember hearing someone mention such a device.

__________________
" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles

It's an electronic device and it needs an electronic signal.........found on the W-126..........but not the W-123.

provide us with the VIN and we'll see what it says.
Whatever the case, unless it is a Euro version, your instrument cluster is in question. 84 or 85 should have a tach.
Where is your air cleaner? Just to the right of valve cover or more up by the right headlight area?

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

Gotcha. So, is there some type of mechanical adjustment to correct the speedo reading?

__________________
" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles

I remember someone posting not too long ago about taking apart the speedo and adjusting the coil spring. At the fixed end of it, the spring is clamped and you can take it in or let it out, which changes the speedo reading.

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1985 300TD-euro 352,000 mi
1974 240D (1?)52,000 mi - has a new home now

Not ironclad, but we may be able to tell if you post a pic taken from just behind the rear passenger seats from the cargo area (split rear seat and carpeting) and also of the back of the front seats, as if taken from the outside with the rear passenger door open.
Interior pic of of the entire front dash area would also be helpful.

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85' 300D No inspection, No registration fees, Cheap insurance
"If my calculations are correct, when this baby hits 88 miles per hour, you're going to see some serious %$&^."

There is also a mechanical gadget with gears inside that you can buy to adapt different mechanical speedometers. Various gear ratios can be purchased to adapt up or down as needed. The gadgets attach to the speedo cable, usually at the tailshaft.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

are you sure there is no marking on the diff? it should be at about 7 0clock position on the rear below the cover. also post the part number on the speedo- it is on the bottom.

my 84 does not have a tach amp, and it does not have the blue tranny crap.

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

An 85 would have a small square door on the passengers kick panel with an egr computer inside of it.

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1996 E300 110,000
1985 300TD 212,000
1980 300D 238,000

mine are in the hatch across from the spare tire

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1996 E300 110,000
1985 300TD 212,000
1980 300D 238,000