Looking for 3.46 W123 diff - New England

[I6dzl]

Anyone got one laying around?

I am in eastern CT

TIA

[ridgerunner]

I've got a couple W123 diffs. I'll have to look at them and see what the ratio is.

[I6dzl]

Originally Posted by ridgerunner

I've got a couple W123 diffs. I'll have to look at them and see what the ratio is.

Really trying to find something local. Unless you wanna ship it real cheap...

[ridgerunner]

Oh, ok. Last time I shipped one, it was @ $25-30.

[Grzpdlr]

Originally Posted by I6dzl

Anyone got one laying around?

I am in eastern CT

TIA

Sure you want another 3.46, might be a good time to go lower. Just a thought.

[fonzi]

Are the wagon rear ends the same as what you are seeking? @rwd4evr definitely has a manual diesel wagon he is parting with a 3.46 rear end.


Sent from my iPhone using Tapatalk

[I6dzl]

Thanks for the replies. After some more research, I am going to go with a 3.07 diff instead. This is for my 4spd stick 240D I use as a highway commuter.

So, if anyone in New England has a 3.07 diff they want to part with... let me know!

[fonzi]

I’ve got a few 3.07 from r/c107 cars which I’m pretty confident fit. However, if you are looking for a smaller 6-cylinder differential, and not the bigger stronger v8 differential, I don’t believe we’ve got any of those in a 3.07. I think all of our 6 cylinder rear ends have a higher ratio, 3.46 or higher.


Edit: I also really doubt that a 240d will be able to get out of its own way with a 3.07 in it. Be ready for some slow acceleration there. I’m guessing you’ll be lucky to ever get onto the highway for your “cruising”.

I will check the EPC for a stock 240d ratio though. I honestly don’t know what their stock ratio is.

Edit: in the EPC, I couldn’t find any 240d ratio below 3.69. There are versions with 3.92, and even over 4 I believe. I did find a thread where someone says for the last year of the w123, they did a 2.88, but that doesn’t seem to apply to the 240d.

If you do move forward with a 3.07, it will be interesting to hear how it performs. That’s the same rear end that was used with most 4.5 liter v8 cars. But I guess it all depends on how your transmission is geared. If you aren’t going with a stock MB transmission, you may be just fine with a 3.07... or maybe even with a stock MB trans. I don’t know.

Edit again:
It looks like the 300d turbo diff is the bolt-in you are seeking. But there’s a significant difference between the 300d turbo and the 240d. Right?


https://**************.com/node/2588


Edit:
And this topic seems to cover someone wanting to put a 2.88 in a 240d with great resistance.
http://www.benzworld.org/forums/w123-e-ce-d-cd-td/1565495-240d-2-88-gear-rear-3.html


Anyway, you will probably need to retitle the thread or start a new one.

[I6dzl]

I am assuming I have the 3.69 now. I have been using this page as a reference. I actually spoke to the guy who runs that page and has a 4spd 616 power W115 I think it was? But same drivetrain and tire size with a 3.07 and he said he would absolutely do that swap again over the 3.46 I was considering.

http://mbturbo.com/gear-ratios/

All stock drivetrain in my car. If it sucks, I will find a 3.46 to put in it.

Also found this post, Kent said he has done a 300D turbo rear (so should be 3.07) end swap on many 240Ds and he doesn’t seem to feel the loss on the low end outweighs the lowered highway.



I have tweaked my IP a bit and bumped timing. The car feels very strong (for a 240D ) right now on the highway from 50mph on up in 4th. Truthfully, I would swap a 3.27 but it doesn’t seem like that is something I’ll realistically be able to find.

I have found very few people documenting their experiences after the fact with a manual trans 240D and rear end gear changes but the few I find are happy with 3.07s. I planned to write a thread up after I made the swap.

[I6dzl]

Local guy is dropping off a 3.46 diff for me Sunday morning... with any luck, I’ll be commuting Monday morning with it.

I will report my findings

[fonzi]

Originally Posted by I6dzl

Local guy is dropping off a 3.46 diff for me Sunday morning... with any luck, I’ll be commuting Monday morning with it.

I will report my findings

So you decided to not go for the 3.07?

I did read up a little, and can see that the 3.07 is doable, but it could be a little harder on the clutch if you’ve got to feather it more often getting started up a hill or something.

[I6dzl]

After driving home on the highway yesterday from work and understanding that my RPM at 58 would now be my RPM at 70, I’m not sure it will have the power to do anything but cruise on flat ground. It’s somewhat hilly around here.

I will make a thread and report back after it’s done. If it seems like there is no issue, maybe I’ll hunt for a 3.07 diff to swap.

[fonzi]

Cool. Hearing that you’ve got hills, it’s possible you would have ended up cooking your clutch quickly. It’s possible we will never know. 3.46 seems like a pretty good all-around ratio.

My 1985 280sl has a 3.58 and it will get up and go, but it’s really not like the 3.69 that was in my 1981 280slc 4-speed. I found myself often trying to shift into a non-existent 5th in the 3.69 with no OD. Here are the ratios.


While with the 3.58, I find myself very often running in 4th on the highway for the extra power. Here are the ratios on that car:


I notice the slower acceleration in all the first four gears with the 3.58, and that 2.91 final OD ratio just doesn’t seem to have the guts, even with the m110 185 HP motor. Sure, I will eventually get past people on the highway, but it is laborious in comparison to today’s cars. This may be why I find myself leaving it in 4th quite often.

The 3.58 1:1 is pretty comfortable for cruising, more-so than the 3.69. That’s with the nicely revving m110 DOHC gas motor. I don’t know whether the diesel feels like it would be ready to shake itself apart at higher RPMs (not having ever driven a MB diesel).

In any case, I’m going to say, 2.91 is too low (and notice it’s not much lower than 3.07). 3.69 is not horrible, but certainly leaves me wanting a lower gear. 3.58 is pretty damn nice.

I’m thinking you will be pleased with the 3.46.

Hopefully you won’t find yourself having to go to third (1.45 probably) very often. That’s the equivalent of 5.00 with a 3.46, the same as the 3rd (1.398) in my 1985 280sl 5-speed. It’s not so insanely high that you won’t use it for passing, but hopefully you won’t find yourself “living there” because it would defeat the purpose. You might ask yourself how much time you already spend in 3rd gear with your current 3.69. If it’s a lot...

Maybe get your hands on a 5-speed 717.4xx transmission which will probably have ratios like mine. Or just get a 300D turbo motor.

[I6dzl]

Most of my driving is between 55 and 75mph. Power feels pretty good for highway cruising and maintaining speed on grades right now between 60-65. I’d prefer to cruise a little lower rpm at 75 without sacrificing too much of that power so I think a 20% gear drop is too much. I think 3.46 will be a good compromise. 75 is about the fastest I drive, rpm will drop from 3720 to 3488 with the 3.46s.

[fonzi]

I agree!


Sent from my iPhone using Tapatalk