Mercedes-Benz Forum

Mercedes-Benz Forum (https://www.benzworld.org/forums/)
-   W123 E,CE,D,CD,TD,TE Class (https://www.benzworld.org/forums/w123-e-ce-d-cd-td/)
-   -   3.69 Rear End in my Euro 280E? (https://www.benzworld.org/forums/w123-e-ce-d-cd-td/3026424-3-69-rear-end-my-euro.html)

BORG47 05-17-2019 11:26 AM

3.69 Rear End in my Euro 280E?
 
Greetings again,

After watching one of those Mercedes-Source episodes where he swaps out the rear end in a 240D, I became curious about what differential gear ratio I had in Rusty. When I had scraped away the road grime from the edge of the housing with the numbers on it, I finally had part of my answer. My reason for the question is that I am not sure the 3.69 is original to the car, and I want to know about the driving characteristics of that ratio with my M110 straight-six and automatic transmission. There were also a few other numbers listed before the listed ratio, "044281", that I cannot decipher. Can anyone tell me about this setup, and does anyone have any opinions of it?

I don't have any pictures, mostly because it was difficult enough squeezing under the car and avoiding banging my head on the exhaust silencer (which didn't quite silence me!).

christuna 05-17-2019 11:38 AM

your car should have a 3.58 ratio diff so maybe someone swapped one from a 240D or carbureted 230

swampmonkey 05-20-2019 05:24 AM

And its a w123 and not w114?

Ive worked on two 280 engines, one being a w114 had the 3.69 diff, the 380CE c123 had a 3.58.

Its not that big of a difference between the two to be honest, the w114 diff was swapped for a 3.07 to get better MPG, aswell as a more comfortable ride.
It didnt feel slower, rather like it had more torque, it pushed better, and had better use of the gears.
For normal driving id do that swap again anytime.

(the 123 have a om602 turbo engine and a fivespeed and was mated to a 2.88 diff, so that would be irrelevant for you :) )

3.69 to a 3.58 swap wouldnt be worth the hazzle if you ask me, unless your current diff is leaking/making noises.

BORG47 05-20-2019 09:25 AM

Quote:

Originally Posted by swampmonkey (Post 17791078)
And its a w123 and not w114?

Ive worked on two 280 engines, one being a w114 had the 3.69 diff, the 380CE c123 had a 3.58.

Its not that big of a difference between the two to be honest, the w114 diff was swapped for a 3.07 to get better MPG, aswell as a more comfortable ride.
It didnt feel slower, rather like it had more torque, it pushed better, and had better use of the gears.
For normal driving id do that swap again anytime.

(the 123 have a om602 turbo engine and a fivespeed and was mated to a 2.88 diff, so that would be irrelevant for you :) )

3.69 to a 3.58 swap wouldnt be worth the hazzle if you ask me, unless your current diff is leaking/making noises.

I'm pretty sure it is a W123!

I would assume a higher gear ratio would be a little less efficient with that motor (engine), but I would also assume it would be able to supply enough torque to the diff (-erential) to make it competent in the traffic we have around here (like Seattle, just without anything cool). The next factor is that I haven't yet driven the car personally, so my opinion is based off of speculation and other people's firsthand experience. How about we pause this thread, I come back in 3 years after I have finished the restoration, and then I ask for insight? If it turns out I like this setup, I will leave it as it is. If it turns out to be less of a perfect ride, keep in mind I am barely at the age I can legally drive this thing!

Judging by how many components are leaky, I am surprised the diff is not losing any fluid. We'll see if it stays that way!

kevdupuis 05-20-2019 10:51 AM

Man i wish I had a set of low 3.0? gears for my 85, watching the tach hitting 3000 rpm while cruising at 112 kmh (70 mph) always makes me cringe.

christuna 05-20-2019 02:30 PM

Quote:

Originally Posted by kevdupuis (Post 17791334)
Man i wish I had a set of low 3.0? gears for my 85, watching the tach hitting 3000 rpm while cruising at 112 kmh (70 mph) always makes me cringe.

i'm preety sure that 3k rpm at 70 is correct with 3.07 gears (remember unlike a lot of other automatics 4th gear in mercedes is 1:1)

and also 1985 was the only year where w123 and w126 turbos got the 2.88 gears so you should have slightly lower rpm unless someone swapped the diff

swampmonkey 05-22-2019 06:02 AM

Quote:

Originally Posted by christuna (Post 17791564)
i'm preety sure that 3k rpm at 70 is correct with 3.07 gears (remember unlike a lot of other automatics 4th gear in mercedes is 1:1)

and also 1985 was the only year where w123 and w126 turbos got the 2.88 gears so you should have slightly lower rpm unless someone swapped the diff

i might be misstaken, but as far as ive understood, the 2.88 was somewhat limited to california or alike.
Us europeans never got it atleast, and i think the same goes for a bunch of US-states aswell.

Dr.Grillz 05-22-2019 09:54 AM

When the time comes and if you're interested, I'll have a correct 280E speedometer unit available in MPH (140mph). This will work with the correct 280E differential with the 3.58 ratio.

christuna 05-22-2019 12:16 PM

Quote:

Originally Posted by swampmonkey (Post 17793038)
i might be misstaken, but as far as ive understood, the 2.88 was somewhat limited to california or alike.
Us europeans never got it atleast, and i think the same goes for a bunch of US-states aswell.

from what I've been reading 2.88 in 1985 was installed on all federal cars but I don't have a source to confirm.

2.88 was also installed on all 1986-1987 300SDL (won't fit a w123 because its a different case)

And yes all euros got 3.07 (only w123 wagon available with turbo no w126 turbo)

1985 california got the 722.4 transmission with different air filter, trap oxidizer and other stuff while other states got the regular 722.3

off topic: I'm visiting gothenburg in 2 weeks :thumbsup:

swampmonkey 05-22-2019 04:35 PM

Quote:

Originally Posted by christuna (Post 17793366)
from what I've been reading 2.88 in 1985 was installed on all federal cars but I don't have a source to confirm.

2.88 was also installed on all 1986-1987 300SDL (won't fit a w123 because its a different case)

And yes all euros got 3.07 (only w123 wagon available with turbo no w126 turbo)

1985 california got the 722.4 transmission with different air filter, trap oxidizer and other stuff while other states got the regular 722.3

off topic: I'm visiting gothenburg in 2 weeks :thumbsup:

Might be that way, ive heard of us 1985s that didnt have the 2.88 either. so i dont know.

Welcome to gothenburg!
if i have time il gladly show you around :)
What are you doing here then?
Il drop you a message


All times are GMT -7. The time now is 07:28 PM.

Powered by vBulletin® Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.