Turning off your car at 55 mph


#121

well, the converter is the last connection to the engine, so in slowing down the converter has to be the thing pushing the engine.


#122

As we head towards the magical 200 mark I could ask what’s located between the converter and the driveshaft.

:slight_smile:


#123

If engine braking was done solely inside the transmission, the RPM of the engine wouldn’t rise. You can notice the same brief rise in RPM when coming to a stop and the transmission normally downshifts through the gears to first. Obviously the transmission is turning the engine, and the fluid coupling (torque converter) will transmit torque the other way too.

I hate to disagree with arguably the most knowledgeable person here when it comes to automatic transmissions, but if I interpret your statement correctly, I must.


#124

I never said engine braking was solely done inside the transmission. Engine braking COMES FROM the transmission, NOT the converter. The converter is the link between the trans and engine. In order for someone to know how a converter works, you have to have a basic understanding how an automatic transmission works and how they actually work together.

I am officially blue in the face, and the dead horse has been beaten bloody. Indy should have some sort of answer by now.

I’m done here…

transman


#125

C’mon guys… just a little more. We’re reaching that 200 comment mark :slight_smile:


#126

transman, here is exactly what you said “Engine braking is done inside the transmission by way of overrunning clutches for example. Not by converter operation.”

Technicly the engine braking comes from the engine thru the converter to the tranny to the driveshaft to the differential to the axles to the wheels to the tires. oblivion is CORRECT. Good Grief!!!


#127

He can’t admit he was wrong!!


#128

I couldnt resist.

Ellis said: Technicly the engine braking comes from the engine thru the converter to the tranny to the driveshaft to the differential to the axles to the wheels to the tires. oblivion is CORRECT. Good Grief!!!

Engine braking DOES NOT come from the engine, it STARTS in the transmission. Drive your Dodge 2500 to 50 mph then drop your gear selector into L2. When your transmission downshifts to 2nd gear you will feel engine braking. The transmission shifting to a lower gear will raise your RPM’s. This is engine braking and it originated from the TRANSMISSION thru the converter. The engine will slow the transmission down but it cant happen until the transmission tells it to do so. So engine braking originates from the TRANSMISSION. Please dont give anyone on this site transmission advice, you just dont understand. Stick with what you know, maybe your 50 years + driving skills. You could be a great help there.

transman


#129

Actually he’s not wrong. He said that engine braking originates from the transmission which is true. It all has to do with vehicle speed and gear ratio. That will determine how much if any engine braking you will get. I didnt read this whole thread but will try when I can sit long enough. I am also a transmission guy, 35 years in the business and too much grey hair for my own good.


#130

Well, Robert, there would be no engine braking if the torque converter was not doing it.


#131

Well, transman, you said it yourself. "This is engine braking and it originated from the TRANSMISSION thru the converter."
Thru the converter.
The engine is doing the braking, not the transmissin! If the engine or the converter were not in the vehicle, the transmission would be of no effect.


#132

Other than the fact that no answer has been provided about where the fluid pressure is coming from to actually cause the transmission to work let me pose this one.

You’re working on an engine in the car and the job you’re doing (timing chain/belt, set of rod bearings, timing the crankshaft to a distributor, etc, etc) requires that the engine be rotated by hand.

This is usually done with a ratchet/socket on the crankshaft bolt. The engine can be freely rotated while the transmission is in PARK, DRIVE, or whatever without rotating the transmission output shaft, driveshaft, or rear axle.
If the logic used is that there is a pure mechanical connnection (as in gear tooth to gear tooth which it’s not) then explain why the engine will rotate freely without causing any movement in the driveline.

(Transman has asked for it now. Lady + drivers license at 16 + 50+ years driving experience = age inference and tail whuppin’.) :slight_smile:


#133

ok4450 you said “If the logic used is that there is a pure mechanical connnection (as in gear tooth to gear tooth which it’s not) then explain why the engine will rotate freely without causing any movement in the driveline.”

There is NO mechanical connection between the engine and automatic transmission. Unless someone wants to call the converter a mechanical connection. There is a lockup clutch in the converter but it will not work until the vehicle is going a certain speed and will not work with the key off. Since the converter is a fluid connection, and needs to be spinning to do anything, thus the engine can be rotated without any part of the driveline moving.
Also it has been explained where the fluid pressure was coming from to keep the engine turning while slowing down. A. If you are driving at any reasonable speed and you turn off the engine, the pressure remains until the engine is turning too slow to maintain the pressure. Now we have established that this is not true with late mocel Ford vehicles, and maybe some others.
Hard to understand??


#134

Just being curious of course, but I’d like to hear a bit about your mechanical background.


#135

I used to be a mechanic but now I am a Rocket Sientist. You say you are a mechanic but you have come up with the most ridiculious statements.
This all started when transman said that a torque converter could never push an engine. Than he said it might for 2 to 4 seconds. Well I tried it with my Dodge on 4 different hills and with the engine turned off going downhill, the engine turned for at least 24 seconds. I never lost power to the steering or brakes, and the engine held the van back so much that it almost stopped before I reached the bottom of the hill. don’t know how long it would have but I reached the bottom of the hill, turned the ignitin on and the engine fired up and I went on. I believe that speed not time is the factor. There are others on here who have had the same results as have I.

now you guys say that engine braking depends on the transmission. Well it takes a transmission and a Torque converter both to get engine braking. Why is it called “engine braking” if it is the transmissin doing the braking.
I guess you are a professional mechanic, but I surely wouldn’t bring a car to you for repair.


#136

The torque converter is only a small part of the whole picture. You need the transmission in there. The engine cant slow the vehicle without the transmission controlling it. What you are saying is right but you are only covering a part of the whole thing. Engine braking is nothing without the transmission. Gear ratio in the transmission controls how much if any engine braking you get. Just like Transman said, engine braking starts and is controlled by the transmission. Like it or not, he’s right.


#137

I don’t care how you explain it The engine is what slows down the vehicle when you let off the gas. You say without the transmission the engine can’t slow the vehicle. Of course thats right. Without the differential or the wheels on the ground it won’t work either. Why is it called “engine braking” instead of “transmission braking”

“The engine cant slow the vehicle without the transmission controlling it” Is the stupidest thing I have heard about this subject. The transmission can’t slow the vehicle without the converter or the engine. Are there any “brakes” in the transmission? ’


#138

This whole argument started when transman said that a Torque Converter would never push an engine. I proved that mine would and he has never accepted it. I have told several times on here how I proved it and have gotten arguments from 2 or 3 others. I have gotten posts from others who say they have had the same experience.

So I guess I will rest my case. I hope you guys research a little more, you’ll find out I am right.


#139

Whether you like it or not Earl, thats how it works. You dont have to like it but thats the way it is. I dont like the rising fuel costs but thats the way it is whether I like it or not. Get over it. You are getting so delusional over trying to prove me wrong on something I have been familiar with for the past 27 years. Even another tranny guy with more years than me came forward and told you the same thing. Get over it and move on.

transman


#140

I asked a civil question and get a sarcastic answer rather than an honest one?