1987 300TDT Transmission (?) Issue? - Page 2 - PeachParts Mercedes-Benz Forum

1987-300TD · #16 12-16-2014, 03:12 AM

The UPS lady showed up today with a brand new set of Febi Flex Discs today! Put a big smile on my face! :-)

Things to note on these discs. They have "Made in Germany" printed on the actual disc as well as the box. They come with 6 hex bolts. I mention the hex bolts as the rear disc on my car has all 3/4" SAE bolts. The front disc has 3 x 3/4" SAE and 3 hex bolts. I dove into the project around 8pm. I quit around 11pm.

I started by jacking up the passenger side of my car (Picture 01). I then took a better picture of the rear diff and its caked on grease and dirt (Picture 02).

In order to get to the drive shaft, I discovered I needed to remove a "shield" to gain access. The shield is secured by 3 x 8mm screws, 1 in front and 2 toward the rear. To remove the front screw, I used an 8mm ratcheting box wrench from HF.

My vehicle had the catalytic converter removed by a previous owner. I am not sure the best procedure to access the shield and drive shaft if you still have your catalytic converter. I removed the rubber donut from from the driver side of the muffler. This gave a little extra wiggle room to remove the shield.

Next I started unbolting the rear flex disc. I took note, per jay_bob's recommendation, that the rear diff bolts should have the threaded side of the bolt pointing toward the front of the car (Picture 06). Whomever did the rear seems to have bolted them properly. There is even a Mercedes diamond on the disc itself. I have ZERO idea how many miles are on these discs.

Alas, I was only able to remove 3 of the bolts. The 3 on top were inaccessible. Do I need to rotate the tires while I have the rear in the air to access the top bolts?

With the shield off, I took pictures of the center bearing and u-joint (Pictures 07 and 08). Should I lubricate the u-joint somehow? Any procedure to remove the bearing or just remove the 2 bolts and it should be obvious?

I could not remove any of the front bolts. I could not figure a way around the transmission mount. Do I need to support the transmission with a floor jack and remove the transmission mount to be able to remove the front flex disc bolts? Is there some crazy tool?

Whilst under the car, I started cleaning the rear diff. Picture 09 is some of the grease I removed. Picture 10 is the shield soaking with engine degreaser. Picture 11 is the "cleaner" rear diff. Picture 12 is a close-up of the "cleaner" diff. It even has a part number. :-)

Lastly, I found the rear diff drain plug. It appears to need a hex wrench for removal. I did not readily find the fill hole. Any guidance on where the fill hole is?

I will continue to update and share pics. Thank You for any insights!!!

1987-300TD · #17 12-16-2014, 03:14 AM

More Pics...

jay_bob · #18 12-16-2014, 09:02 AM

You will need to get both sides of the rear in the air. You do have to put the transmission in neutral to be able to spin the shaft around to get to the other bolts.

Differential filler plug is higher up on the side of the diff above the drain. Another big hex socket bolt. Be sure to remove the filler before removing the drain. AeroKroil is your friend here.

Use Valvoline Synthetic 75W/90 gear oil, comes in a squeeze bottle. Open the drain, let the old oil drain out (overnight is best), flush the interior with brake cleaner, follow with compressed air to dry it out, when you can't smell brake spray any more, close up the drain, and fill it until the oil reaches the level of the filler hole.

In order to get to the front flex disk you do need to release the transmission mount. You will need to use your floor jack and a broad, flat piece of wood (like a 2x10) to spread the load. Put the floor jack under the transmission pan and only jack it up just enough to support the transmission while the rear mount bracket is off. Good time to renew this mount bushing as well.

Center bearing does come apart with the two bolts holding the clamp. Be sure to put witness marks on the two halves of the shaft first. You want to make sure those go back in the same orientation.

Get a couple good pictures of your CV joint boots while you're down there.

sixto · #19 12-16-2014, 02:38 PM

Quote:

Originally Posted by jay_bob

You will need to get both sides of the rear in the air. You do have to put the transmission in neutral to be able to spin the shaft around to get to the other bolts.

With an open diff such as is standard in a 124.193, you should be able to spin the prop shaft with one driven wheel off the ground (park brake not engaged).

Sixto
MB-less

1987-300TD · #20 12-16-2014, 03:06 PM

Thank You jay_bob and sixto for your replies. I will be working on this more tonight. My goal is to get the rear flex disk off and replaced this evening. I will also be draining the rear diff. Hopefully it is still full of oil. :-)

Either of you have insight on lubricating the u-joint? Is there something I should do with it?

jay_bob · #21 12-16-2014, 03:32 PM

Quote:

Originally Posted by sixto

With an open diff such as is standard in a 124.193, you should be able to spin the prop shaft with one driven wheel off the ground (park brake not engaged).

Sixto
MB-less

Duh, you're right. I forgot that was how it worked.

When vstech and I did my wagon we had all 4 corners up in the air. Made it real easy to get to everything all at once.

jay_bob · #22 12-16-2014, 03:34 PM

The center bearing assembly is easily replaceable in the field by mere mortals.

But not the u-joint. If the u-joint is notchy I would take it to a driveline shop and have them service/replace the joint.

Just remember to mark the shaft halves so they go back together in the same relationship. They are factory matched and balanced as a unit.

1987-300TD · #23 12-19-2014, 02:16 AM

I was back under my car on Wednesday night. I removed a bunch more of the dry, caked grease from the rear diff. I was also able to remove the rear section of the drive shaft (after making a slight mark on the 2 halves).

As with most projects, removing the last bolts from the rear flex disc were super easy and the job went very easily Literally, the last bolt was a royal pain in the a$$! I am including pictures of the rear flex disc.

The next pictures are of the drive shaft bearing and support. Please note you can see light between the outer steel ring and the inner rubber. This is most obvious in the 3rd picture.

The next pictures are of the front section of the drive shaft with the bearing support removed. Also a picture down the area where the rear shaft section belongs.

Next are 2 pictures of the u-joint. It moves readily. There is a "notch" right in the middle of any rotation of the joint. It is akin to a radio dial for center or fader where there is a divet where the middle is...

Lastly are shots of the rear diff and the rear diff drain plug. I felt all over the diff and could not find the fill plug. I found a video which stated it may be on the driver side top of the diff. Does this sound familiar to anyone? Is the drain a 14mm hex?

I have all the parts and am looking forward to working on the project between Friday night and Saturday.

1987-300TD · #24 12-19-2014, 02:19 AM

Pictures part 2

1987-300TD · #25 12-19-2014, 02:21 AM

Pictures part 3

sixto · #26 12-19-2014, 02:33 AM

You can almost see the fill plug in Pictures part 3 picture 3. It's just ahead of the driver side axle flange on a parallel centerline. A twitch higher and not as far forward as the ABS sensor on the passenger side.

In Pictures part 3 picture 4, is the jack stand under the inboard joint of the main LCA or under the diff crossmember?

Sixto
MB-less

1987-300TD · #27 12-21-2014, 03:20 AM

Tonight was another evening under my car. Progress is slow but steady.

Sixto - the jack stand is under the diff crossmember. The inboard joint is covered by some kind of "plastic" covering. Very slippery stuff. Found the crossmember a much better choice. :-)

Also, thanks for pointing me to the fill plug. My rear diff is draining overnight. I sprayed brake cleaner in to clean once the oil drained. Dare I say there was probably a full quart that drained. Dark but I will get a better look tomorrow. As there was quite a bit in there, does that mean that my diff is probably not leaking? I have had several engine oil leaks. Still hunting one in the front of the engine... Could they have caused the buildup on the rear diff?

***** I do have a new question regarding the drive-shaft. As the drive-shaft has a bearing in the center, how does one remove it for replacement? I have a brand new Febi bearing to put on in its place. Is there a procedure for that?

Thanks for any advice!

glenn

compress ignite · #28 12-21-2014, 04:15 AM

Mercedes Benz Model 124 - OM602, OM603 Maintenance Manuals

Propeller Shaft (Driveshaft) instructions:

41 Propeller Shaft

Rear Axle instructions:

35 Rear Suspension and Axle

Center bearing and support R+R instructions:

http://www.w124performance.com/service/w124CD2/Program/Chassis/41-100.pdf

A personal note: ( I do hope a long enjoyable service history accrues to your repairs)
But,as you were reminded earlier,use Genuine Mercedes Parts ONLY, for these repairs
if you ever have to do them again.

jay_bob · #29 12-21-2014, 08:33 PM

Oil soaked diff *could* be due to engine oil spraying backwards off the engine, the diff hangs low and it could be catching it. But I would keep an eye on it and see if it comes back.

Parts brand thread: http://www.peachparts.com/shopforum/diesel-discussion/347300-dang-you-%FCro-other-tales-woe.html this is why you have to be careful about non-genuine MB parts...

sixto · #30 12-22-2014, 02:11 AM

I highly doubt oil spray from the engine could do that to the diff without depositing as much or more grime along the way. The exhaust pipe and resonators would be caked as well.

Sixto
MB-less