Hi

I have recently bought a 1985 126 280 SEL (Euro), and when I was looking around a friends 420 SEL, I noticed that he has a switch on the auto gear selector, for E and S modes. I was wondering if this was an option, as I dont have any selection switches at all! Can this be fitted?

Also when driving at 60 mph the engine speed is at 3000 rpm. Is this normal, as on my other cars 60 mph is around 2400 rpm. Also why do MB lock the torque converter at these higher speeds, or is my box faulty?

Finally what is 4matic? I wanted to change the diff oil, and when I went to get new oil, they asked me if it was 4matic, or had a limited slip diff, what is that?! how do I find out? I know my auto box is 4 speed, but nothing else!!

Sorry for the amount of questions, but I'm really stuck!!

Thanks for any help!!!

Peter.

Can't answer all of your questions, but here's a start:
AFAIK, the E and S mode trannies went with the V8's; as yours is a 6, it will probably have a different tranny and definitely a different rear axle ratio--which would be the reason for the different RPM at 60 mph. A smaller engine typically will have to work harder for its living, and will be geared to turn higher at a given speed.
4Matic was the name MB used for their 4-wheel-drive system; cars that have it typically carry the word on a trunklid badge.

__________________
Craig Bethune

'97 SL500, 40th anniversary edition

'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)


SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)

RPM to speed relationship sounds normal for 4th gear in a 6cyl S-class.

How do you know the torque converter is locking? MB transmissions in those years didn't have a locking torque converter?

One way to tell if you have limited slip, lift both rear wheels and spin by hand one wheel with the transmission in Park and park brake disengaged. The wheel should spin freely and the wheel on the other side should spin the other way. If there's resistance, you probably have limited slip. You can pull the rear cover of the differential to know for sure. I doubt your car has limited slip.

I've never heard of 4Matic being offered with the M110 engine or in the W126 body style. If there aren't any drive axles going to the front wheels, you don't have 4Matic.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

Hey thanks guys!!

That makes sense to me now!!

I guessed that the torque converter is locking because of the fact that when I take my foot off the gas the the rpms stay up high with the road speed, and I asumed this because on my Toyota, when I take my foot off the gas the engine speed drops a lot, and the only way I can get the engine speed to stay up high with the road speed is by pressing the button on the shift, to lock the torque converter.

But I'm sure I'm wrong. I am definatly no expert!!

Peter

Here's what the owners manual for my 86 Euro 500 SE says about program selector swicth. "S" standard, with gear selctor in drive the vehicle will start off in second gear when accelerating gently .The vehicle the vehicle will set off in first when accelerating briskly. (yes set off?)
E Economy, With gear selector in Drive the vehicle will start off in second even at full throttle.
3000 at sixty seems very high my car is only turning 1800 at sixty great for the Autobhan
and MPG but not a stoplight rocket.....
William Rogers........

I guess my transmission is setup, by the way you describe, to only run is 'S' mode. If all what 'E' mode does is to only allow start off in 2nd, then I'm not really getting much of a difference then now, as 85% of my start off's are by accelerating gently.

I thought the same as you did about the rpm and road speed. But as Sixto said, its a 6 cylinder car, and I know its real heavy!!
I guess comparing a mercedes to any other brand or standards is wrong.

I wanted to ask this though, as the car was parked up for 4 years, and when it was used again the gearbox wouldn't change except by placing the shift in neutral and then back in drive. 4th gear would still not engage until I had the control box cleaned.

I wasn't sure if there was still a problem or not.

Peter

Are you sure that it's shifting into fourth? 3000 at 60 would mean a top speed of only 120, where are the shifts marks on your speedo? My SE shift marks for full throttle are it shifts into third at 80 and fourth at 138 I have'nt tried to find that in third but I have taken it up to redline in second.I would think that A Euro twin cam 280 would be geared for European style driving and should have a top speed well over 130......
william Rogers......

Well if I move the gear selector from D into 3 whilst at 50, the engine revs quite high. I havent tried it at any higher speeds.

I am too not sure about the rpms, as you said the car is built for Europe (it is actually full German spec) therefore you would think that it would be able to do 60 at a lower rpm. Even when I drive it, I always feel that I need an extra gear!

I looked on the speedo for the shift marks, but there are none. Also there is nothing in the speed section of the on dash computer that tells you anything.

Are there any official factory specs for gears and road speed available?

I used to drive a Euro 280SEL. It had a 3.46 ratio, and turned 3,000 at 60mph. Believe it or not, the torque convertor hasn't locked up all the way yet at those speeds. Get up to around 120, or so and it should be at around 5850 rpm (+,- 100 rpm).

You DO have a 6500 rpm redline, you know, so there's more flexibility than in the later M103 powered S-Class cars with the same rear-axle.

If the 280 topped out it's redline, it would probably indeed be in the mid to high 130's range, I guess. Maybe even low 140's.

I think at top end the ratio between rpms to speed is about 2.2:1. Meaning the speed you're engine is working (say 4,000 rpm) and the speed you are actually going (with 2.2:1 as the ratio it would be about 88 mph fully locked up).

There is a site with a 260SE going 202kph(about 126 mph) turning just less than 6,000 rpms. This car would be relevent to your car in gearing.



Click here for the picture

__________________
1987 300SDL (324000)

1986 Porsche 951 (944 Turbo) (166000)

1978 Porsche 924 (99000)

1996 Nissan Pathfinder R50 (201000)