The speedometer cable on the 1984 300DT has failed, time to install a new one. I'm having trouble getting a 10mm socket on the transmission bolt so that I can remove the speedo cable from the transmission. Do I need to remove the transmission mount or is there an easier way to loosen it? thank you for any help or assistance....

IIRC, I had to stick an arm down along side the driveshaft to gain access to that bolt. It's not easy. But I did not remove anything else to get the job done.

Give yourself as much clearance under the car as you can, then look at it from a few angles. You should be able to find a way. It may have to be by feel, but that's when you get that rare intimate moment with your Benz...

__________________
'85 300TD "Puff The Magic Wagon" - Rolling Resto
'19 Mazda CX-9 Signature - Wife's sled
'21 Morgan 3-Wheeler P101 Edition
'95 E300d - SOLD
'84 300TD "Brown Betty" - Miss this one
'81 240D "China Baby" - Farm grocery getter

I use a 1/4" ratchet and a extension to remove it.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Thank you to those who gave great advice on how to remove the speedometer cable from a 1984 300DT. I used an extension and a 10mm socket (had to angle it in there but it worked).

I put some ATF in the previous speedo cable; this may be why it failed. Quite a bit leaked out when I removed it. In addition, some of the ATF appears to be gunking up the square hole in the transmission so I cannot tell which way it is facing. I'm thinking of using battery cleaner or perhaps Simple Green to clean off the excess ATF so I can get a clear view.

I think the only lube that I would put in a speedo cable is one of the graphite-based ones. I can't think of graphite spray I have but it goes on like a spray oil, but drys to a powder finish.

__________________
'85 300TD "Puff The Magic Wagon" - Rolling Resto
'19 Mazda CX-9 Signature - Wife's sled
'21 Morgan 3-Wheeler P101 Edition
'95 E300d - SOLD
'84 300TD "Brown Betty" - Miss this one
'81 240D "China Baby" - Farm grocery getter

The square drive hole for the speedometer in the transmission appears to be gunked up with ATF. I need to clean it so that I can see which direction the new cable should be inserted. I'm thinking either battery cleaner spray or perhaps Simple Green degreaser. Any ideas which cleaner would be better?

I cannot fathom how atf would gunk up a speedometer drive... do you mean it's gunked up with dirt soaked in atf?

__________________
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'd just spray some brake cleaner in there... wear face mask!

__________________
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!

Will do. and yes, from what I can see, it looks like possible dust mixed with ATF. My eyesight isn't what it used to be so I'm going to try a magnifying glass to get a better look at which direction the square is facing so I can properly seat the new cable. Thank you for the brake cleaner suggestion!

I'm having difficulty lining up the square end of the new speedometer cable with the square hole in the transmission. I'm thinking of putting a light oil lubricant (3 in 1 oil or gun lubricant) on the square end of the cable so perhaps the cable will slide into the hole easier. I've got the car up on ramps and a bright halogen light. Also using a magnifying glass to determine which way the hole in the tranny faces. This is driving me nuts! EDIT: This is on the 1984 300DT.

There are a couple of things that I needed to understand about inserting the speedometer cable

1) Make sure you have the right one. MB changed the cables several times and the shape of the end changes from cable to cable, as does the overall length of the cable (by the way, you didn't mentioned which car you're working on... I am answering based on my experience with the W123)

2) Although I had the correct cable for my VIN, I compared it carefully to the cable that came out of the car, and realized that the tip of the cable was a few mm TOO LONG. In other words, although the shape was correct, the old speedometer cable had a shorter tip. The new cable's longer tip caused the tip to 'bottom out' on the hole in the transmission drive, and this made it impossible to fully-seat the cable. This was confirmed through using a caliper to check the dimensions.

As a result, I needed to grind a few mm off the end of the new speedometer cable until it would no longer bottom out. After that, it went in properly and has worked flawlessly for several months. To be honest, this is the first time I've ever had a MB factory part not be exactly to specifications.

Good luck!

Packman

__________________
83 240D - 4 speed manual - Manilla Beige
189K miles, Tachometer mod, cool wooden shift knob from PeachParts, CocoMats, Original factory paint, manual windows, manual sunroof. Starting to add AudioWrap to this car too!

OK, I carefully examined the old cable and to my surprise found that it broke off. I suspect the broken end is still buried in the transmission. any ideas how I can remove it so that I can install the new cable?

After careful examination, it appears the old speedometer cable broke off in the transmission. It appears the broke off piece is still buried in the transmission. any ideas how to remove it? This is on the 1984 300DT.

Magnet?

__________________
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!

I just tried a magnetic pick up tool that fit up into the slot quite nicely; no joy. any other ideas?