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Discussion Starter #1
My 1985 300D (CA) has broken teeth on the ring gear. Any details on pulling the transmission would be much appreciated. At this point, I've drained the transmission fluid from the Torque Converter and Transmission Case and removed the two bolts supporting the exhaust pipe near the bell housing.

My next step is disconnecting the tail pipe at the rear of the vehicle so it can drop down out of the way and separate the transmission from the drive shaft. This is already a challenge (separating the drive shaft) since two of the four bolts (both on the passenger side near the exhaust pipe) are turning, but not un-threading from the nut - the problem is in trying to hold the nut since the access to it is extremely limited.

Once I accomplish the above steps, it seems I need to remove all connections to the transmission, support the transmission and proceed to remove the bolts from the bell housing. A mechanic friend several hundred miles away said it would be best to "keep the torque converter with the transmission."

I believe I understand how to attach the new ring gear using a torch (thanks to a youtube video). I'm apprehensive to proceed, but well committed to see this through one way or another. Any advice/suggestions/tips are much appreciated. Once I learn whether the 12 bolts attaching the flywheel are 12 point or allen, I will know whether I will have to replace them or not (if they are allen). Recommendations on where to purchase the ring gear and bolts are appreciated as well. I've seen ring gears ranging from $60-120 and the bolts ranging from $7.19 - 12.00 each.

Brian
 

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....I believe I understand how to attach the new ring gear using a torch (thanks to a youtube video). I'm apprehensive to proceed, but well committed to see this through one way or another. .....
You’re best bet is to get a used flywheel and balance it to the original.

But if you have to go the route of a new flywheel ring gear, then the procedure calls for the ring gear to be drilled and broken up with a chisel or heated and quickly pounded out. After the ring gear is removed clean out any debris and check for any damage.

To install, the ring gear is to be heated even in an oven to temperature near 220º C (428º F). Since the ring gear is hardened, the procedure calls that should not have any part of the ring gear go over 220º C to prevent the hardness from loosing integrity. Also not getting it close the 220º C will not allow the ring gear to expand enough to get it installed over the flywheel. You will use a Laser Thermometer or a multimeter with a temperature sensor to determine the correct temperature and once it is close, with some heat resistant gloves, the ring gear should just slip right over. Using a torch is the last resort, but not recommended because it is harder to control the evenness of the heat and may develop hot spots that will affect the metal hardness.





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Discussion Starter #3
Source for a used flywheel ('85 300D) and other tips?

1985 300D - Since I am yet to gain access to the flywheel, replacing it with a used one is still an option to putting on a new ring gear. Does anyone recommend a source for a used flywheel with a good ring gear and what does "balancing it to the old flywheel" mean and how is that accomplished?

My latest successes involve: 1) Supporting the transmission and removing the cross member that supports the transmission mount. 2) With that out of my way, I was able to remove 3 bolts from the drive shaft.

My latest challenges involve: 1) identifying a black tube which runs to the back of the transmission that would seem be loosened with a 10 mm socket. It's not wanting to be removed easily. 2) disconnecting the drive shaft - I mistakenly thought removing the three bolts that attach the drive shaft would allow separation. I was wrong.
 

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1985 300D - Since I am yet to gain access to the flywheel, replacing it with a used one is still an option to putting on a new ring gear. Does anyone recommend a source for a used flywheel with a good ring gear and what does "balancing it to the old flywheel" mean and how is that accomplished?..
You can get one from your local wrecking yard if they have 300D or 300SD 617.95x engines in stock.

Basically they flywheel is balanced to your crankshaft. You must keep the same orientation when you reinstall the flywheel. So be sure to note the position. You will then take both flywheels to a reputable machine shop and have them match balance the new flywheel to the old.


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My latest challenges involve: 1) identifying a black tube which runs to the back of the transmission that would seem be loosened with a 10 mm socket. It's not wanting to be removed easily. 2) disconnecting the drive shaft - I mistakenly thought removing the three bolts that attach the drive shaft would allow separation. I was wrong.

The tube you speak of is most likely the speedo cable. Once you remove the bolt, just tug it out. It may take a bit of persistence to get it out though.

You will need to unbolt the center support bearing and then take a prybar to separate the flex disk to the transmission. If not enough room, then you'll need to unbolt the flex disk from the differential. Make sure you mark the orientation of the two piece driveshaft at the connection. If you happen to separate the two and don't know the orientation, it will cause a vibration. Also make the orientation to the trans flange and diff flange to ensure that an imbalance will not happen.



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Discussion Starter #5
Update: Flywheel access - How many bolts attach the transmission to the engine?

Well, I'm either making progress with this project or digging myself a deeper hole - time will tell! At any rate, I appreciate your comments.

Progress includes disconnecting the drive shaft from the transmission. If I understand correctly, it isn't adequate to merely loosen the speedo bolt; it needs to be removed for cable removal. That will happen tonight.

Besides the speedo cable, there appears to be a small diameter cable that attaches to the top of the transmission. Any clues to how it is removed?

The transmission is supported by a jack and I believe I've removed all of the bolts attaching it to the engine; yet it doesn't seem to be free. Counting the two bolts that attach the starter, how many bolts are there that fasten the transmission to the engine? Are there any bolts higher than the higher of the two which hold the starter?
 

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....
Progress includes disconnecting the drive shaft from the transmission. If I understand correctly, it isn't adequate to merely loosen the speedo bolt; it needs to be removed for cable removal. That will happen tonight.
Yes remove the bolt.

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Besides the speedo cable, there appears to be a small diameter cable that attaches to the top of the transmission. Any clues to how it is removed?
Not sure what your referring to. But the only small diameter line would be a vacuum line to vacuum modulator which just unplugs from the connector.

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The transmission is supported by a jack and I believe I've removed all of the bolts attaching it to the engine; yet it doesn't seem to be free. Counting the two bolts that attach the starter, how many bolts are there that fasten the transmission to the engine? Are there any bolts higher than the higher of the two which hold the starter?
I think there are a total of 9 bolts for the bellhousing. Two at the top, two starter bolts, one bolt beneath the starter holding the exhaust mount, and two at the bottom (passenger side holding the exhaust mount). On driver's side one bolt with the ground strap and top of that, one bolt held down with a nut. In addition, you have 6 13mm bolts holding the torque converter to the flywheel that can be access from the window at the bottom of the bellhousing.



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Discussion Starter #7
Making progress, but not there yet!

In order to remove the Bowden cable at the transmission, I dropped the pan. What is the best approach to fishing out the cable. Does anyone have an image that shows how the end of the Bowden cable attaches to the transmission? Just as I am struggling with removing the cable, I anticipate it won't be easy to reattach it when the time comes.

Talk to me about the six 13 MM bolts attaching the flywheel and the torque converter. When will I remove these bolts - before or after the transmission is removed? Also, review the critical points of alignment: 1) Driveshaft to flex disc is marked so that they can be reassembled as they were to avoid vibration. 2) I'll have the flywheels balanced and install the replacement according to the original. Are there any other places where I need to make sure to mark parts to ensure proper alignment is retained?
 
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