My indie mechanic has suggested that I drive around in "3" in my '87 300SDL,when I'm cruising around the city,up to around 40 mph...use "D" for higher speeds and rpms.Can I take this suggestion to mean it's not a bad idea to use "S" while cruising around in an '83 240D??Are the "'3" in the 126 and the"S" in the 123 comparable??TIA for the usual variety of good advice!

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2001 E320 4matic, 2003 E320 4matic wagon

why not just put it in drive? why does he want you to put it in 3rd and "s"?

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have no worries.....President Obama swears "If you like your gun, you can keep it

Good suggestion from that mechanic. I always drive in slow traffic in "3" in the '87 300D. Keeps the brakes from wearing and warms up the engine better if its cold. Engine dynamic braking. I can't seem to teach my wife to do that however
the 240D is a different set of conditions however

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

I agree with the mechanic. The SDL will perform better in third around town. It's a dog when it shifts to fourth.........when you want to accelerate at 30 mph it's a PITA unless you downshift. The engine will be happier and you will be happier.

The 240D, with its 3.69 gears, will be screaming in third at 40 mph........you won't be able to stand the noise.

I always cruise about in 3rd in my L and the SD up to about 45mph. After that it is 4th (D, 1:1) to get RPM back down.

Turbo will be on the boil and less wear on the trans.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

i put it in drive in my 350sdl and leave it there.

but the 350 is pretty torquey.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Just leave it in drive. There's no real benefit to leaving the shifter in "S" around town. You don't just need higher RPMs and more fuel flow, but you need more air flow as well to clean out the engine, which you get best at a high load, like high speed driving, or Italian Tuneups.

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

45 is fine for a 300D in 3rd. For a 240D, 35mph is better for the gearing

A thread like this comes up from time to time on another board I'm on-http://www.crownvic.net. On that board, it's generally known that the Ford AOD tranny has a weak 4th (overdrive) gear and should not be cycled more than needed. With the 722 MB trans, I am aware of no such weakness. My Benz goes in D before I leave the parking lot and there it stays.

BTW, my Sammy has an even better setup. It goes into whatever gear I choose, when I choose-manual 5 speed. I wish all my cars were manual (pauses for poetic reflection about slushbox-loving American new car buyers)

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

Yeah it only has a 1.5" OD band stock. I have a 4R70W OD setup in mine currently, still on stock 2.40:1 first gear which is a bit lame but the close ratios (1.47:1, 1:1, 0.67:1) are nice with a decent rear gear and a 28" tire.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

I drive in S generally in the city for to/from school driving, up till around 40, then I'll drop to D so its not such a high rpm. My car will go from 18mph to 110 in 4th without much complaint, its got enough torque to be "fine" in D at all times, but I enjoy the more sudden "surge" you can get when cruising in S, way more torque. Its likely also better for the engine than going along at 30mph and 1,250 rpm.....

Ever since I mentioned driving in "S" to my dad as an option, he tried it, and now does it for most of his driving, even up to about 50-55mph!!

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

I just stick it in D and go... around town youre at about 1800-2000 RPM or so in 4th gear which is perfect for low rpm torque/diesel engines.

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1985 CA 300D Turbo , 213K mi

I'm so glad I don't have to fight my tranny for control anymore. Now I choose when I want to change gears! All I need now is to find a 5-speed for the highways.

"warms up the engine better when cold"

wouldnt this have the same effect as flooring it? holding it in 3rd just makes the engine turn faster. i dont like to really open up the throttle when the engines cold.

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have no worries.....President Obama swears "If you like your gun, you can keep it

Turning faster creates more internal friction in the engine and requires a bit more fuel......so.......it will warm faster in 3rd than in 4th......everything else being equal.

Flooring it will warm the engine very fast........but.......it's not all that pleasurable for a cold engine.