W123 Driveline Sizes

[charmalu]

I have a project coming up with the 85 300D, changing out the automatic transmission and swaping in a 4 spd manual. I have a 240D front section that will have to be cut, welded and balanced along with the rear section.

The car has 343000 miles on it now, so I was thinking of replacing the rear section with one from PNP that has less miles on it. I dragged one home with 225000 miles from another 85, but today I pulled one from a 79 300D that has 130900 miles. I know the spedo`s may not be accurate and sometimes run slow or stop and all that. I saw this car when it came in Jan 8th and it was a real cream puff, very clean, good blk interior, 1/2 shafts almost no cracks etc. only crack on dash is next to the right speaker, about 3/4 inch. this might be going in my 85 also .

Now the length of the rear drivelines from the rear flange to the end of the splines where the two halves fit together, are all the same whether 300D, 300D turbo, or 240D whether manual or automatic from everything I have seen or read about. don`t know about the W123 gassers, they may be the same also.

The diameter of the tube is around 2 1/4 inches from all I have seen. the one I pulled off the 79 300D is 2 1/4 on both ends, but coming in form both ends about 4 inches the tube expands to about 3 1/8 inches. this one heavy duty looking sucker. The front section is the same size as all others I have seen.

So I should be able to use this fat rear section, along with the 240D front section that will be cut after careful measurements I would assume?

Any one seen one of these fat drivelines?

I didn`t say it above, but the reason I was thinking of using a driveline with less milage, is because of the U-Joint in the center. I know these go 300000 mile or more. I just don`t want any problems down the road later if I can help it.

Charlie

[lutzTD]

I used the rear section from my coupe and a shortened 240D front section on my swap. Mine being a coupe the length of the front section may or may not be different than yours. But you should be fine. Many say balance them together but my shop said he couldnt do it and the way he welded and machined there should not be a balance issue anyway. He said if it was out of balance you can put on a hose clamp and move it until you have it balanced ut.The only other thing to think about is to observe the DS from one of your parts cars and try to orient the 3 bolt flange the same in relation to the u-joint. i did not do that and it is one of my list of suspects in my drive line vibration at 1700 rpm.

[t walgamuth]

I have several spare ds lying about. They seem to come in different diameters. I have never noticed a set pattern. I suspect the turbo cars would have the fatter ones for strength. I would use the fat ones on a turbo car if I had them, but if I didn't I probably would use whatever I had on hand and not worry too much if I didn't.

[charmalu]

Tom, actually the turbo cars, my 85 included, that I have come across at PNP have all been the thiner DS. this fat one I pulled yesterday is off a 78
5cyl NA engine. not a lot of romping stomping horse pwr there .

A 240D is like 68 HP, so add one more cylinder, 85 HP? that`s 17 HP per hole. the Turbo eng is only 123 HP, that`s 24.6 HP per hole. Hang on.

Before I pulled it, I did some measurments with a 240 next to it to make sure it was the same length. when got home I lined it up with my spare one, and the same. just fatter.

The gasser w126 usually are fatter and with larger rubber disc than even the 300SD.

LUTZ, I remember reading that thread you posted about your driveline and other trans swap threads. has been helpful. I have a note pad with every 4 spd swap, clutch bleed, vibration problem, trans mount, thread I have come across. I have been studying for the final exam .
seems like I read that the 85 has a different size hole in the crank for the pilot bearing and it has to be machined to fit. more searching to do.

Charlie

[lutzTD]

Originally Posted by charmalu

Tom, actually the turbo cars, my 85 included, that I have come across at PNP have all been the thiner DS. this fat one I pulled yesterday is off a 78
5cyl NA engine. not a lot of romping stomping horse pwr there .

A 240D is like 68 HP, so add one more cylinder, 85 HP? that`s 17 HP per hole. the Turbo eng is only 123 HP, that`s 24.6 HP per hole. Hang on.

Before I pulled it, I did some measurments with a 240 next to it to make sure it was the same length. when got home I lined it up with my spare one, and the same. just fatter.

The gasser w126 usually are fatter and with larger rubber disc than even the 300SD.

LUTZ, I remember reading that thread you posted about your driveline and other trans swap threads. has been helpful. I have a note pad with every 4 spd swap, clutch bleed, vibration problem, trans mount, thread I have come across. I have been studying for the final exam .
seems like I read that the 85 has a different size hole in the crank for the pilot bearing and it has to be machined to fit. more searching to do.

Charlie

I have learned a few things along the way, so post your swap and all of us can comment along the way. you wont be sorry, I love the manual in mine. I now have a 300D flywheel and I will be putting that in along with my 5 speed in a few months once my honeydew list gets paired down.

[charmalu]

I`ll document things as I go along. Iam good at taking pictures of most things I do. Just haven`t figured out how to post them yet on the forum.

Posting them off site like Photo Bucket is good for now. But down the road a few yrs they may not be there. seen that when looking at an old thread and just a bunch of red X`s. Doesn`t help the new person coming on board.

Posting on MB Shop server, even thumb nails, at least they will be there later on. some can be expanded on which helps.

I keep going back to PNP looking for that elusive 300D flywheel and 4 spd set up or even 5 spd, hopeing one show`s up before I start the project.

These things are just under our noses sometimes and don`t see them. I was at the Hose Shop picking up some Hydraulic parts, and Linus the part`s guy sold one for $600.00 some one gave him for FREE.

Charlie

[KAdams4458]

Originally Posted by charmalu

Tom, actually the turbo cars, my 85 included, that I have come across at PNP have all been the thiner DS. this fat one I pulled yesterday is off a 78
5cyl NA engine. not a lot of romping stomping horse pwr there .

Boy, you got that right. I was looking at pictures of driveshafts back when I was preparing to buy a diesel W123 for the first time, and for obvious popularity reasons, most of the photos you find on the Internet are of the later turbo cars. When I crawled under my '77 300D for a pre-purchase inspection and got a look at its driveshaft for the first time, my first thought was, Why the Hell does this thing look like it belongs on a school bus?

Several salvage yard trips since that day have confirmed that later cars had a normal looking driveshaft, and the oldies have something that looks like it could drive the prop of an Ohio class sub in comparison.

I wish I understood why.

[charmalu]

Doing some searching I came across this old thread. a little update here.
I mentioned in the first post I had a driveline out of a 79 300D with 130K miles on it. so I used it thinking the U-Joint would be good compared the the miles I had on my original DL with 343K.

I swapped in the 4-spd trans and used the 79 DL and had the front 240D piece shortened and every thing balanced. about 20K miles later working through some vibrations etc... I discovered the U-Joint was a little loose. so out it came and had the Drive Line shop replace the Joint. They machine it out and use a Ford Mustang greaseable joint, and held in with clips. so is easily replaceable down the road if ever needed again.

I uses South Bay Drive Line in San Jose, also had them do the joint in the 240D. they replaced the 2 end bushings, center support and joint for $300.

Charlie

[t walgamuth]

Cool, thanks for the update.