Can you feel the slippage of the fluid coupling in an auto tranny?

[sugarwood]

Torque converter, fluid coupling, etc.

Does an auto tranny feel noticeably less responsive?

At speed, there is a lockup converter for 1:1 transmission.
But, prior to that, like when accelerating from a stop, can you feel any slippage?
Not slippage from a failing tranny, but that loss of efficiency from fluid transfer.

[Oh Haha]

Dude, you need another hobby. j/k


The slippage cannot be felt with an automatic unless you change out the torque converter for one with a higher stall speed. With most cars the slippage is barely noticeable.

Drag racers will choose a stall speed that closely matches the RPM that the engine starts making power.

In my old Camaro with a small block Chevy 400 I had a 3500 RPM stall converter. The car wouldn't move much until you got the revs up to around 2000 and be locked in around 3000.

When launching in a race you would apply the brake and throttle. When you released the brake and mashed the gas the engine RPM would go to 3500 giving you a quick start. It would be similar to "dumping" the clutch in a manual transmission car.

[wdfifteen]

50 years ago you could feel it. It was like the gas pedal was connected to the carburetor with a rubber band. But they have gotten tighter and tighter over the years. Now - I can't feel a thing. I worked on the early GM lock-up torque converters and they were awful. You could feel a noticeable jerk when they locked up and at 30-35 mph they would lock and unlock constantly.

[masraum]

Originally Posted by Oh Haha

Dude, you need another hobby. j/k

+1

The slippage cannot be felt with an automatic unless you change out the torque converter for one with a higher stall speed. With most cars the slippage is barely noticeable.

I'm not sure that I agree with that. To me, 98% of the autos that I've driven do not feel as solidly, mechanically connected as a manual trans with the clutch engaged. And the feeling changes when temps change and under varying driving conditions.

I believe that you should be correct however. A torque converter should provide an essentially solid connection once it's hit it's stall speed. Maybe what I'm thinking about and really stands out in my mind is off idle which is when the torque converter is not yet locked up or maybe when going from coasting to back into the throttle.

Most modern trannies are leaps and bounds better.

I absolutely agree with what you said about torque converters and drag racing.

[Bob Kontak]

Originally Posted by sugarwood

But, prior to that, like when accelerating from a stop, can you feel any slippage?

No. Not one God damned bit, even in an old Ford Windstar.

What is the basis for you question? Why are you asking this?

Do you have a 1950's Desoto with Fluid Drive or are you just bored?

Jeebus H Christ. Chill on the silly open ended questions.

What would you do with the feedback if it was articulated to your satisfaction?

I am serious. State the reason for asking this and what will you do with the information?

I had a weird aunt. Should I post questions about her idiosyncrasies and ask the membership for analysis?

[Bob Kontak]

Originally Posted by masraum

I absolutely agree with what you said about torque converters and drag racing.

I had a 65 Skylark with a small V8 and a switch pitch. Low 17's I bet.

[herr_oberst]

I had a 64 skylark with the Rover/Buick V6. I would have done cartwheels if I could have gotten that thing into the 17's.

[Bob Kontak]

Originally Posted by herr_oberst

I had a 64 skylark with the Rover/Buick V6. I would have done cartwheels if I could have gotten that thing into the 17's.

Mine was a 4 door but it did scoot. Relatively speaking.

They were nice looking cars.

25+ MPG if you drove like a wimp as well.

Just to make you green with envy, it had a Buick 8-Track under dash player added a few years after new.

Zeppelin, all day, every day. It clicked to the next track in the middle of "Battle of Evermore". "Bring it back.....Bring it back...Click".

[cgarr]

What car??

[Bob Kontak]

Mid sixties Skylark for my post.

No idea where sugarwood is coming from.

[herr_oberst]

Originally Posted by Bob Kontak

Mine was a 4 door but it did scoot. Relatively speaking.

They were nice looking cars.

25+ MPG if you drove like a wimp as well.

Just to make you green with envy, it had a Buick 8-Track under dash player added a few years after new.

Zeppelin, all day, every day. It clicked to the next track in the middle of "Battle of Evermore". "Bring it back.....Bring it back...Click".

2 door HT here. Wish I would have kept it. I was a fool to let it go.

[Bob Kontak]

Originally Posted by herr_oberst

2 door HT here. Wish I would have kept it. I was a fool to let it go.

Two door. A big hell yeah! Even the four door was pretty.

[masraum]

I had a '65 Impala 2dr, '70 Skylark 4dr, and briefly a '69 Riviera.

[GH85Carrera]

I had a 1960 VW bug that turned low 30s in the 1/4 mile at almost 45 MPH. The transmission was pretty automatic. I never had to really think about it, my foot hit the clutch and my hand mover the gear shift pretty much automatically.

[masraum]

Originally Posted by Bob Kontak

No. Not one God damned bit, even in an old Ford Windstar.

What is the basis for you question? Why are you asking this?

Do you have a 1950's Desoto with Fluid Drive or are you just bored?

Jeebus H Christ. Chill on the silly open ended questions.

What would you do with the feedback if it was articulated to your satisfaction?

I am serious. State the reason for asking this and what will you do with the information?

I had a weird aunt. Should I post questions about her idiosyncrasies and ask the membership for analysis?

Thanks for the entertaining rant. I often wonder sugarbritches (j/k) is getting on about too. Oh, and BTW, maybe you need to switch to decaf.

[Oh Haha]

sugarbritches! I laughed out loud at that.



Sugarwood--if we didn't like you, we wouldn't mess with you.

This forum is full of folks that have a vast knowledge of just about anything so your questions, although a bit unusual at times, will probably net you a pretty good answer.

[asphaltgambler]

To answer your question: The only fluid coupling lies solely with the torque converter. In older vehicles say 50's / 60's the technology was pretty crude. If anything the auto trans set-ups of that era was intended to slip and gear changes were like butta most were only 2 speeds forward. Also many of the trans cases were actually cast iron!

But as we all know, as HP / TQ increased and the cars became heavier heat became the primary issue for trans failures as well as poor lubricant quality then. Even by the late 60's early 70's there was a lot more hard science and engineering that went into eliminating slippage and reducing friction and rotating weight / mass.

In the late 70's there was the 1st appearance of lock-up torque converters which eliminated any slippage at speed but the down side was these were still mated to largely dated 3-speed designs coupled with very tall, low numerically rear gearing which lugged the engine down to point which if it even thought about misfiring, you'd feel it like a shock.

Modern auto transmissions are so advanced with at least 5 speeds forward, the engineers can computer model design the torque converters targeting the most efficient stall / then lock-up for each combination. As a note, the majority of modern trans lock the converter up by 2nd gear.....

[aschen]

of course in nearly any auto car, it is easy to feel (and see on the tach) a slightly non linear relationship ( and time dependancy) between engine rpm and vehicle speed.

If you push slightly on the gas pedal the rpm rises just a little before the speed increases. this is slippage in the torque converter.

wait have you never driven a an auto car?

[Pazuzu]

Automatic transmissions ("slush boxes" among some folks) never slip at all.

None. They would be wasteful to the environment if they slipped. How would mother nature like it if we had cars that used gas while not accelerating forward?

That's why you have to take them out of gear every time you stop at the stoplight, otherwise they would stall. Since they don't slip. At all. Ever. None. Never. No slippin' here. No way for the engine to keep running while the transmission is still in gear, yet the drive assembly is not turning. No way at all, that would require slipping. Which they don't do.

[Pazuzu]

Of course, it doesn't matter any more, since fly-by-wire cars have taken all feeling out anyways...you couldn't tell if the tranny was slipping, since the computer has already decided that you mashed the pedal too fast, and it's actually going to slowly ramp up the throttle body, despite your concerns about that car barreling down upon you...stupid crappy technology...