Possible problem with 85 300 SD, I'd appreciate inputs.
 

Hello Everyone, I'd love your input on this potential problem.

In my 85 SEL, (which has an 83 SD motor), When Im driving at 60 mph or so, and I take my foot of the throttle, the car slows down very slowly,

in my 85 SD, and im driving at 60 and I take my foot of the throttle it slows down really quickly, much faster than the SDL,

So the question is which one is working correctly... From what I know about diesels I would get that the SDL is working correctly, and there is something wrong with the SD, My worst case scenario (in my mind) suggests that turbo on the 300 SD, is causing a drag on the motor,

I would love your inputs.

thanks.

I'd bet $100 the SEL has a higher ratio rear end vs the SD.

From AdSitCo:
380,500,560SEL : RATIO 1:2.47 ABS
300SD 85 : RATIO 1:2.88 ABS

Higher ratio means the engine turns slower at a given speed and less engine braking effect.

Turbos can't create drag on the engine, my bets are on the higher rear end in the "SDL" as well.

i too think it has to do with the gear ratio, thats what it sounds like

nothing is "broken" on ur car....

Thanks guys, yeah you are probably right, definitly right about the rear end having different gears, just for curiosity what would be the symptoms of a dead turbo, would the car be a real dog to drive?

dead turbo= heavy smoke, slow as hell, no turbo sounds"not good ones at least" and poor fuel economy

Check to see if the throttle linkage is hanging up, also make sure the spring is hooked up at the back of the IP.

"I'd bet $100 the SEL has a higher ratio rear end vs the SD.
From AdSitCo:
380,500,560SEL : RATIO 1:2.47 ABS
300SD 85 : RATIO 1:2.88 ABS"

Mabee when they printed the Adsit catalog this is from they didn't have any SDL rear ends in stock. Mine says the above, and also 300SDL 1:2.88 ABS, so it is the same as an '85 sd. A ratio of 1:2.65 used in the '87 300d would have been better.

Actually Mark, the previous posts were correct, since my "SDL" was really a 500SEL in a previous life, I replaced the V8 with a 83 SD (617), So the car has the higher rear end gearing. I really like the 2.47 rear gearing, car loves it on the highway, I would definitly recommend it to anyone, Also anyone who is planning or doing an swap from Gas to diesel in a w126 can msg me, and ill try to post some helpfull hints.

My mistake, I should read more carefully before posting. The rear end ratio is one reason your car is better than a stock SDL, not that it needs to be pointed out. If a 500sel with a blown engine is found nearby, I might be renting a engine hoist and parting the '84 300d.

maybe check the compression and leak down time. you may have too many miles on the rings in that motor... but the rear gearing is probably the reason. the SDL is also heavier than the SD Yes?
John

brakes?
 

Could it be the brakes? That happened to my mom's car (a pinto, I think) many years ago. The car would slow down fairly fast when one took their foot off the acellerator -- faster than one would expect with just coasting. Apparently a caliper had siezed. Car just slowed to a stop one day on the freeway, stranding her. A new caliper or two and it didn't slow like that anymore.. coasted real nice then.

Come to think of it, I dunno why we didn't hear it rubbing. Maybe the winter salt corroded it so fast we couldn't hear it on account of the windows being rolled up and the heater being on full blast all the time.