Speedometer Part Number Check for 87 300TDT - PeachParts Mercedes-Benz Forum

1987-300TD · #1 12-11-2014, 01:10 AM

My odometer has been broken for over a year. The speedometer seems to be about 5 MPH slow. Researching the problem let me to the conclusion that it was not the original speedo from the car. Something about the 87 300TDT having a different rear diff than every other 124 that year. :-)

I grabbed an instrument cluster from an 88 300 gasser wagon from the local pick a part. The part number is:
124 542 60 67

Will this work properly in my 87 300TDT? Before I invest the time in "fixing" this speedo, I want to make sure it is the correct part. If so, I will "repair" the device before gears start slipping and all the other associated problems with the speedometers from this era.

Thank You!!!

glenn

jay_bob · #2 12-11-2014, 08:33 AM

Here is the info on what ratios the rear ends of all 124s are. You will need one from the same ratio as your wagon. You have a 2.65 rear end ratio.

Most common models that have that same speedo:
1987 300D (the same car as yours but a 4-door)
1990-1992 300D-2.5 (4-door, 5 cylinder engine)
1993-1995 E320 (gas powered 4-door)

Note that the tach will absolutely not swap between a gas and Diesel.
If you get a junk yard cluster from a post 1990 the lighting will be better, so use that cluster in your car, but you will have to swap the tach over if it is a gasser. The fuel-oil-temp pod will exchange pre/post 1990 and gas/Diesel.
http://www.w124performance.com/docs/mb/other/differentials.pdf

vstech · #3 12-11-2014, 09:38 AM

Quote:

Originally Posted by jay_bob

Here is the info on what ratios the rear ends of all 124s are. You will need one from the same ratio as your wagon. You have a 2.65 rear end ratio.

Most common models that have that same speedo:
1987 300D (the same car as yours but a 4-door)
1990-1992 300D-2.5 (4-door, 5 cylinder engine)
1993-1995 E320 (gas powered 4-door)

Note that the tach will absolutely not swap between a gas and Diesel.
If you get a junk yard cluster from a post 1990 the lighting will be better, so use that cluster in your car, but you will have to swap the tach over if it is a gasser. The fuel-oil-temp pod will exchange pre/post 1990 and gas/Diesel.
http://www.w124performance.com/docs/mb/other/differentials.pdf

I'm sure the 93 300D also has the 2.65 (it's what we put in your wagon!)

JamesDean · #4 12-11-2014, 10:26 AM

Quote:

Originally Posted by jay_bob

Here is the info on what ratios the rear ends of all 124s are. You will need one from the same ratio as your wagon. You have a 2.65 rear end ratio.

Most common models that have that same speedo:
1987 300D (the same car as yours but a 4-door)
1990-1992 300D-2.5 (4-door, 5 cylinder engine)
1993-1995 E320 (gas powered 4-door)

Note that the tach will absolutely not swap between a gas and Diesel.
If you get a junk yard cluster from a post 1990 the lighting will be better, so use that cluster in your car, but you will have to swap the tach over if it is a gasser. The fuel-oil-temp pod will exchange pre/post 1990 and gas/Diesel.
http://www.w124performance.com/docs/mb/other/differentials.pdf

I was thinking...

If he was to use a speedometer from a differently geared car, I wonder if he could change out the drive gear on the odometer and that would resolve the mileage issue...but that would still leave the speedometer out of calibration. I've not dived into them that much to know what needs to be changed to fix that. Hmm.

1987-300TD · #5 12-11-2014, 12:33 PM

Thank You for the replies! I am still a bit confused though...Will this speedometer (124 542 60 67) actually work in an 87 300TDT?

Also, why will the Tach not work from a gasser? Does the Tach have a part number somewhere? I doubt very highly that my instruments are original. I would like to get something accurate. :-)

Again, Thank You for the help!

JamesDean · #6 12-11-2014, 12:55 PM

According to the EPC that part number speedometer was only used on 124.050 (300CE) and 124.030 (300E).

While the speedometer and odometer will function they will NOT be accurate.

The tachometer from a gasser runs on a slightly different signal than that of a diesel and MIGHT function but largely be inaccurate.

capflya · #7 12-11-2014, 01:16 PM

The speedometer will work, but it may not register the correct speed/mileage.

sixto · #8 12-11-2014, 04:27 PM

Quote:

Originally Posted by jay_bob

Most common models that have that same speedo:
1987 300D (the same car as yours but a 4-door)
1990-1992 300D-2.5 (4-door, 5 cylinder engine)
1993-1995 E320 (gas powered 4-door)
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Same diff ratio which means the speedos are interchangeable but not necessarily the same speedo. Gasser speedos go to 160 mph with no loss of accuracy in a Diesel. Some cars have an ASR/ASD warning indicator at the 12 o'clock position. I don't think any US '87 had a traction control option.

'93 300E/TE 4Matics have a different diff ratio.

Sixto
MB-less

vstech · #9 12-11-2014, 04:53 PM

Quote:

Originally Posted by 1987-300TD

Thank You for the replies! I am still a bit confused though...Will this speedometer (124 542 60 67) actually work in an 87 300TDT?

Also, why will the Tach not work from a gasser? Does the Tach have a part number somewhere? I doubt very highly that my instruments are original. I would like to get something accurate. :-)

Again, Thank You for the help!

The tach on a gasser gets its signal from the spark ignition system that the diesels don't have.
Diesels need a crank rotation sensor and the supporting bits to drive its tach.

1987-300TD · #10 12-11-2014, 06:50 PM

So, to confirm, the speedo I have (124 542 60 67) will work but not accurately.?.

As I pilfer through my local pick-a-part, for which part numbers should I be looking?

Anyone have one for sale at a good price? :-)

capflya · #11 12-11-2014, 08:43 PM

As listed above by jay_bob:

Most common models that have that same speedo:
1987 300D (the same car as yours but a 4-door)
1990-1992 300D-2.5 (4-door, 5 cylinder engine)
1993-1995 E320 (gas powered 4-door)

I found some 94-95 E320's in the local pNp and snagged the speedometers for both of my w124 diesels.

jay_bob · #12 12-11-2014, 09:40 PM

Quote:

Originally Posted by vstech

The tach on a gasser gets its signal from the spark ignition system that the diesels don't have.
Diesels need a crank rotation sensor and the supporting bits to drive its tach.

124 Gas tach comes from the ignition system - the gassers are I-6 so they have 3 sparks/rev

124 Diesel tach comes from the ring gear sensor - 144 teeth on the ring gear so 144 pulses/rev

The gas tach on diesel buries itself at 7k as soon as the engine is started...

jay_bob · #13 12-11-2014, 09:42 PM

Quote:

Originally Posted by vstech

I'm sure the 93 300D also has the 2.65 (it's what we put in your wagon!)

Nope, my speedometer came from mbselect's 95 (?) wagon that ate the chain link fence.

1987-300TD · #14 12-12-2014, 02:49 AM

My sincere apologies on this one for not quite understanding. Are the specific speedometer part numbers that would work with my car:
124 542 54 67 or 124 542 56 68
124 542 59 06 or 124 542 45 65

I understand certain models from specific years shared the same part. Alas, without specific part numbers, I cannot guarantee the right part from pick-a-part. It seems many of these instruments are relatively interchangeable (albeit not necessarily accurate).

Thank You for your patience.

JamesDean · #15 12-12-2014, 10:36 AM

Quote:

Originally Posted by 1987-300TD

My sincere apologies on this one for not quite understanding. Are the specific speedometer part numbers that would work with my car:
124 542 54 67 or 124 542 56 68
124 542 59 06 or 124 542 45 65

I understand certain models from specific years shared the same part. Alas, without specific part numbers, I cannot guarantee the right part from pick-a-part. It seems many of these instruments are relatively interchangeable (albeit not necessarily accurate).

Thank You for your patience.

It looks like the only part number compatible units are the second

124 542 59 06 or 124 542 45 65

The other units are for Canada and are likely in KPH only.