How does 126 #3 compare to 123 "S"?

[dbgrate]

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!

[kmaysob]

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

[dieseldiehard]

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

[Brian Carlton]

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.

[Hit Man X]

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.

[t walgamuth]

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

but the 350 is pretty torquey.

tom w

[kmaysob]

Originally Posted by dieseldiehard

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

"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.

[Brian Carlton]

Originally Posted by kmaysob

"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.

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.

[Hatterasguy]

I noticed the SD seems to be geared lower then the L. So around town in D is fine for me.

I usually keep the L in D as well because I don't want to listen to the engine spooling up. My windows are down 99% of the time in the summer so I have to listen to it.

I believe that most people who drive in S do so to avoid a lot of unnecessary up-shifting and down-shifting between 3d and 4th. My indy recommends it for that reason. Personally I don't bother, but I don't spend much time in city traffic anyway.

Originally Posted by kmaysob

"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.

How do you open up the throttle on one of these IDI diesels?

Someone is showing evidence of the gas affiar they have been having hah.