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Registered
1985 W123 200, 1980 C107 450 SLC, 1979 C107 450 SLC
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34 Posts
Discussion Starter #1
Hi

I'm used to driving manual transmissions. I was taught to down shift as I'm coming to a stop, since this will save the brakes from unnecessary wear.

My SLC is my first automatic car and I find myself, as I'm approaching a stop, shifting from 'D' to 'S' at about 60 km/h (40 mph), causing the auto box to shift into 2nd and having the engine assist in braking.

Is there any reason why I should not be doing this? Is this particularly bad for the gearbox and/or gear selector?

Thanks
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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32,355 Posts
+1^^^

And where are you now? Please fill in your profile with your location, year and model.

Welcome to the forum.
 

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Registered
1985 W123 200, 1980 C107 450 SLC, 1979 C107 450 SLC
Joined
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34 Posts
Discussion Starter #4
Thanks for the welcome.

I'm from South Africa (where the brake pads are expensive:) ).

I'm well aware that the brakes will be much less expensive than working on the 'box, hence why I would like to know if it is a bad idea to shift down. If shifting down like this puts unnecessary strain on the gear selector mechanism or any other part, then it is surely a better idea to leave braking to the brakes.

It is a 1980 model with 111 000 km on the clock.

P.S. I'll update my profile as soon as the paranoia subsides :D
 

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Registered
'79 450SL
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255 Posts
these cars are meant to be driven, I wouldn't worry about downshifting at the speeds you mentioned.
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
Joined
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32,355 Posts
P.S. I'll update my profile as soon as the paranoia subsides :D
We are equal opportunity offenders. :D

As for the down shifting. Fuel economy. Shifter bushings. Mounts. Flex discs. All will suffer a little. Probably insignificant other than the fuel mileage.
 

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Registered
'80 450SLC Afro RHD Ikonengold
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2,900 Posts
You do not have to go to dealership to get brake pads.

I got my from places like Midas or even better, my last Afro brakepads came from ATE dealer (one at Strydom Park, close to Linex Yamaha and Mutual and Federal assesment centre, something like Sun Parts or so).
I think it was close to R100 for set and that's cheaper than enywhere else in the world.
 

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Registered
1978 280slc
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3,203 Posts
Out of habit I think it is a bad idea to use the engine and transmission as a brake. All it takes is 1 downshift that is too aggressive and you can kill the engine by overrevving it. Even in a manual car, I think of downshifting as just keeping the engine at the correct rpm to keep the car moving forward. The engine is there to make you go not slow you down. These cars have great brakes.
 

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Registered
1985 W123 200, 1980 C107 450 SLC, 1979 C107 450 SLC
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34 Posts
Discussion Starter #9
@Djenka. Thanks for the shopping tip.

With all this mind, I think I'll cut down on the engine braking. :thumbsup:
 

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Registered
'80 450SLC Afro RHD Ikonengold
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2,900 Posts
I do no see the problem in downshifting as you'd normally do with a manual as long as you apply the same rules. Same rules of breaking the gearbox while excessive downshifting applies too.
A dose of "normal" is important.
Make sure your flex discs and diff mounts are ok.

IMO, the best braking in daily W107 driving is throttle off at appropriate time.
 

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Outstanding Contributor , Bob's Your Uncle!
-----'83 280 SL----- 5 speed....The PIG
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29,512 Posts
I don't blame you for wanting a little more to do while driving...........thus my 5 speed.

Transmissions were designed to shift up and down.

Brakes were meant to brake.

Moderation to both will make a happy car.

Enjoy the drive.......you only live once...You might as well be happy.
 

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Premium Member
1984 380SL, 1973 450SLC
Joined
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2,174 Posts
Might be a good idea to look for a replacement, The best time to find a replacement transmission is when you don't need one, not saying you will need one soon, it's always nice to have a spare if the price is right,,,, and who knows, you might even be able to sell it for a profit. Not sure how available spares are in your neck of the woods. Drive it like you stole it... if you don't,, someone else will...
 

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Outstanding Contributor , Bob's Your Uncle!
-----'83 280 SL----- 5 speed....The PIG
Joined
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29,512 Posts
My thoughts exactly, but would you mind telling SWMBO that's the correct way to drive? I'm certainly no going to. :D
Nobette drives the automatic in the family. But she'll back out of the driveway and shift to drive before stopping backwards motion.

Drives me to drink.


Thanks, honey.
 

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One of the BW Old Guard/R129, W204 Moderator
1997 SL500- 40th Anniversary
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7,166 Posts
I don't know how I missed this thread.
Shift away, but be prudent and mindful of the rpm's when you do. The "B" position was installed for braking, or so the urban legend goes...:)

If shifting automatics manually was a bad thing, I'd think all the paddle shifter-ricers and "slap-box" Lexus and such would suffer.

Enjoy your drive!
 

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Registered
1987 560SL (L.Tonk) [92,700 miles]
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317 Posts
What about throwing the car into neutral while in motion? The manual explicitly warns against it, but can't figure out how it would cause issue. Or perhaps it's the N->D shift that can put strain on the system if you've not matched revs?

I think the paddle-shifters have much more 'intelligent' clutch systems which allows you to flail away at them without doing much damage (or good). My friend's Lancer has them and I found them pretty much useless in day-to-day driving, plus not nearly as fun as having an actual clutch.
 

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Always Remembered RIP
1979 280sl 4 sp w/ac 1957 MGA 1998 volvo xc/70 2004 F150
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6,050 Posts
It wasn't as much fun as a clutch but the lightning rods in my 84 Hurst/Olds came close and definitly led to more of WTF is that.

 

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Always Remembered RIP
'78 450SL
Joined
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199 Posts
Mark Donohue was asked the same question, and he replied to the effect that an engine/trans was more likely to be damaged than the brakes, as well as cheaper to replace pads than powertrain. He won an awful lot, and I've kept it in mind ever since I read this, and saw it in practice in the late '60's/ early '70's. Not only have I not blowed up an engine or transmission since, but I've developed a trait of not abusing/overusing the brakes over the years, and still braking later than most, left foot/trail braking for the slide, without excessive wear, no rotor warpage, save the tires, and able to carry speed at a good clip. As Paul Horning said, practice practice practice.
 
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