What happens if you drive a 1984 Mercedes 380 in low gear (d3) for a period of time at a high speed on the interstate?
Nothing, other than getting somewhere.
I must disagree with @KiwiME. If you are actually in low gear and are driving at high speed you may overheat the transmission and the engine. Damage can occur to one or both when this happens. Are you sure D3 is “low” gear? I thought D1 was low gear. D3 usually just means that overdrive is locked out in most vehicles. Others may offer more insight since I haven’t seen the D3, D2 and D1 designation for years.
You’ll just guzzle a bit more gas.
Still nothing compared to my uncle’s 70-something 450SEL: what a hog!
No so, missileman … German cars and especially Mercedes are famously capable of driving at full throttle continuously and D3 is not an inappropriate gear for the relatively relaxed speed of a North-American interstate.
Why did (or would) you do this?
It depends on what you mean by “high speed” and “a period of time”. But in my way of thinking, D3 isn’t low gear, at least that isn’t how the gears are usually labeled. D1 is usually low gear. D3 would be one of the higher gears. You’d probably manually shift to D3 driving on a highway, when encountering a steep hill, if you noticed the car was slowing down more than you wanted it to.
The gear you drive in isn’t what is important provided the rpm is within a safe range and the engine isn’t lugging, but if you drive in too low of a gear the rpm may excede the red-line rating for the engine. Or even if the red line wasn’t reached, running at a high rpm could result in higher than normal forces in the engine bearings from the intertial forces from the mass of the pistons oscillating to & fro like they do. That could do some damage possibly.
But because it was D3, I doubt this is something to loose any sleep over.
GeorgeSanJose, I agree with you “Or even if the red line wasn’t reached, running at a high rpm could result in higher than normal forces in the engine bearings from the intertial forces from the mass of the pistons oscillating to & fro like they do. That could do some damage possibly” However there will be some on her that will disagree. They say some engines were designed to run fast and high RPM will do no harm. Just watch, the next post will probably disagree.
If you have an 84 car and are driving in too low a gear…you’ll know it if you are at all familiar with the vehicle. If it’s just one gear off, maybe you won’t notice, but it won 't hurt much either…just a little more wear.
Well. D3 probably isn’t Low gear
That car has a 4 speed automatic, so D3 means 4th is locked out.
The trans should be fine.
I suspect there is more to this story…
Yes, sounds like someone is looking to assign some blame for a mishap…
Look up his other (almost duplicate) question, car’s now in bad shape.
I think your car should “take it”.
How many miles on this Benz?
@KiwiME are you suggesting OP is hoping to get a rebuilt transmission out of this?
On someone else’s dime?
I’m not sure I am reading that between the lines.
In any case, we’re not there.
Whoever’s pointing fingers is going to have to work it out for themselves.
If anybody is in fact pointing fingers . . .
But I think it’s pretty much a moot point, because most/all of us agree that the trans, in all likelikhood, sustained no damage.
Driving in D-3 should not damage anything. I don’t know why the question even came up.
Here’s why the question came up. In his other post, he asked:
“just bought a 1984 Mercedes 380SL and was driving down the road. The car stopped on me a couple of times and I noticed I was driving with the shifter at d3. I stopped for a while and now the car won’t start? Did I do something to the car while driving in that low gear?”
MUCH different question, wonder why he asked this one.
T Stagg, I believe an explanation is in order. We’re always happy to help, but you need to be up front with us.