So this question stems from my recent road trips across Canada and different cities south of the border, I noticed as I'm driving in my 91 350SDL that the car seems to rev really high (I know this has been discussed), I do have a 2.47 rear end in my car that I swap out before I go on any road trips but it still seems to rev high for my liking. This got me thinking about the W140 transmission, my questions are do the W140 with the OM603 come with a 5 speed or were they all 4 speed? and how easy would it be to swap over if they are indeed 5 speed? What are the gear ratio's compared to the W126 350SDL?

__________________
OBJECTS IN MIRROR ARE CLOSER THAN THEY APPEAR, ONLY IN A BENZ

89 560SEC
90 350SDL (Rudolph)
91 350SDL (300SDL drivetrain)
87 BMW 635CSi (Swanhild)
89 BMW M6 (euro)
99 Suzuki Hayabusa (Only the fastest thing ever)

Mercedes Benz EPC 140.134 Chassis Information | Everything Benz

Says no - the automatic transmission fitted is a 722.367 => that'll be a 4 speed auto

Anyway even if a 5 speed auto was fitted I think that top gear would be a 1:1

EDIT - this is wrong for the 722.5 transmission see

http://en.wikipedia.org/wiki/Mercedes-Benz_5G-Tronic_transmission


5 speed manuals or 6 speed manuals have a slight "overdrive" effect say 1:0.85 / 1:0.80 or so

See

S 280 | W140 Mercedes-Benz S Class

for example...

The rear axle ratio on a W140 is meant to be 1:2.82 according to the Russian EPC

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

How high are the revs we're talking about? at what speed? My folks have a 350SD and its fantastic on the highway, never noticed anything like that. Are you sure its getting into 4th gear?

__________________
1991 300 D 2.5 Turbo, 220k
also in the family:
1981 240 D 185k
1991 350 SD 185k
2006 S 500
2005 SLK 350

The 722.5 and 722.6 have overdrive 5th gears. The 722.5 (300SL/SL320 and 300SE/S320 through '96) needs a simple controller so it shifts properly through 4th. Without the controller it shifts from 3rd to 5th which might not be a problem for the way you drive. A 722.6 needs a full blown controller. No two ways about it but there are folks who dabble in standalone controllers. As of 2-3 years ago none were released products but I heard there are working models out there.

Consider the TC stall characteristics before you lower engine rpm. You might reduce engine rpms to the point that the TC slips at cruising speed.

Sixto
87 300D

That's a good point particularly for more modern TCs with a device that locks the drive - what's that called again? A lock out? I'm pretty sure the 722.3 and 722.4 TCs don't have them - but from say 722.5 they might...

PS I've altered the first post I made in this thread to give a link to the 722.5 information on wikipedia - it shows the final drive gear ratio

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Don't get me wrong the car drives great but with the 2.47 rear end based on the GPS driving at approx. 120kph the RPM's sit around the 3000 mark.

__________________
OBJECTS IN MIRROR ARE CLOSER THAN THEY APPEAR, ONLY IN A BENZ

89 560SEC
90 350SDL (Rudolph)
91 350SDL (300SDL drivetrain)
87 BMW 635CSi (Swanhild)
89 BMW M6 (euro)
99 Suzuki Hayabusa (Only the fastest thing ever)

That's the German way.

Sixto
87 300D

It means that you don't have to wait around for the transmission to shift on the highway. My 350 turns the same RPMs.

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.