MolaKule
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Old but Interesting Valvoline ATF Presentation
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Thanks for the site.Found it interesting as it pertains to Dexron. VI
JHZR2
Staff member
The fraction of MTs sold in the US vs the rest of the world is staggering. Nothing but laziness to explain it. Since we finance our laziness, nobody cares, even if theyre still paying the last car in the financing of the next.
Does it comply with Citröen reqs: CITRÖEN/PEUGEOT Z 000169756? The Pentosin ATF1 is recommended, amongst other.
Slide 41, second paragraph is missing a word.
And what's the "anti-shudder" component? My car has a mild shudder when warm and I give some more of the gas pedal. Eletrovalves floating, TCC? ... And the "for life" 2001 oil has about 100k miles.
isn't shudder a form of stick-slip of brakes or clutches? so anti-shudder components would be friction modifiers
Right, it could be from the clutch pack, since i don't know when they act. I had that in my motorcycle wet clutch also when using molygraphite oils.
there's always a combination of clutches and brakes in action in an automatic transmission. Even with a simple 3 or 4 speed there could be 3 brakes and clutches operational at the same time.
Yes, I agree, but I can't get when the clutch act and the shudder occurs, understand?
Yes.
you could try a stall test in 1st, 2nd and reverse etc... maybe that would shed some light at the issue.
you can usually test pretty much every clutch or brake with stall tests in different gears.
you could try a stall test in 1st, 2nd and reverse etc... maybe that would shed some light at the issue.
you can usually test pretty much every clutch or brake with stall tests in different gears.
Really? I thought that was a TC test. Thanks, I'll try that.
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Thanks for posting MK! Very interesting read...
MolaKule
Staff member
Originally Posted By: Pontual
Yes, I agree, but I can't get when the clutch act and the shudder occurs, understand?
Shudder usually occurs at the TCC or torque converter clutch and may be the result of aged fluid, the wrong fluid, worn clutch surfaces, or distorted clutch surfaces due to overheating.
Secondarily, it could be the result of valve varnishing causing under pressure or pressure pulsations (modulation).
Yes, I agree, but I can't get when the clutch act and the shudder occurs, understand?
Shudder usually occurs at the TCC or torque converter clutch and may be the result of aged fluid, the wrong fluid, worn clutch surfaces, or distorted clutch surfaces due to overheating.
Secondarily, it could be the result of valve varnishing causing under pressure or pressure pulsations (modulation).
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MolaKule
Staff member
Originally Posted By: Shannow
Molakule, interesting read, so Valvoline are saying they have a genuine universal ATF...
That would be MaxLife.
Molakule, interesting read, so Valvoline are saying they have a genuine universal ATF...
That would be MaxLife.
MolaKule
Staff member
Quote:
isn't shudder a form of stick-slip of brakes or clutches? so anti-shudder components would be friction modifiers.
Right. One needs the right friction modification chemistry to allow something called, "dynamic friction."
Quote:
In an engine, we want to reduce kinetic friction, but in an Automatic Transmission, we want a specific type of static/kinetic friction.
http://en.wikipedia.org/wiki/Coefficient_of_friction
discusses static and kinetic friction. The frictional characteristics we are discussing here is dynamic friction, a special kind of 'static/kinetic' friction. Dynamic friction is a friction that changes its "coefficient of friction" as two surfaces come in contact and are in relative motion, such as in AT clutch plates.
Recall that clutch plates have alternating layers of clutch friction material and steel plates. The friction material is splined on the inside, where it locks to one of the gears. The steel plate is splined on the outside, where it locks to the clutch housing.
The pressure for the clutches is fed through passageways in the shafts. The hydraulic system controls which clutches are energized at any given moment.
In AT's we want the fluid to create a specific dynamic friction coefficient (dependent upon the clutch materials used) such that we have smooth engagement and disengagement, so we don't have shudder or slippage. Shudder and slippage cause increased frictional material wear and increased heat.
It is this complex package of frictional modifier chemical compounds found in ATF that is important for smooth operation.
Remember, a friction modifier can be a friction reducer, a friction increaser, or one that controls friction in a specified manner.
In an engine, we primarily want friction reduction. In an AT, we want controlled friction modification often called Mu(V) in the literature. The fluid must provide a specific friction versus velocity relationship.
There is a phenomenon commonly called "stick-slip" or "dynamic frictional vibration" and manifests itself as "shudder" or low speed vibration in the vehicle. Using friction modifiers in the ATF prevents this shudder.
http://www.bobistheoilguy.com/forums/ubb...ion#Post1111352
isn't shudder a form of stick-slip of brakes or clutches? so anti-shudder components would be friction modifiers.
Right. One needs the right friction modification chemistry to allow something called, "dynamic friction."
Quote:
In an engine, we want to reduce kinetic friction, but in an Automatic Transmission, we want a specific type of static/kinetic friction.
http://en.wikipedia.org/wiki/Coefficient_of_friction
discusses static and kinetic friction. The frictional characteristics we are discussing here is dynamic friction, a special kind of 'static/kinetic' friction. Dynamic friction is a friction that changes its "coefficient of friction" as two surfaces come in contact and are in relative motion, such as in AT clutch plates.
Recall that clutch plates have alternating layers of clutch friction material and steel plates. The friction material is splined on the inside, where it locks to one of the gears. The steel plate is splined on the outside, where it locks to the clutch housing.
The pressure for the clutches is fed through passageways in the shafts. The hydraulic system controls which clutches are energized at any given moment.
In AT's we want the fluid to create a specific dynamic friction coefficient (dependent upon the clutch materials used) such that we have smooth engagement and disengagement, so we don't have shudder or slippage. Shudder and slippage cause increased frictional material wear and increased heat.
It is this complex package of frictional modifier chemical compounds found in ATF that is important for smooth operation.
Remember, a friction modifier can be a friction reducer, a friction increaser, or one that controls friction in a specified manner.
In an engine, we primarily want friction reduction. In an AT, we want controlled friction modification often called Mu(V) in the literature. The fluid must provide a specific friction versus velocity relationship.
There is a phenomenon commonly called "stick-slip" or "dynamic frictional vibration" and manifests itself as "shudder" or low speed vibration in the vehicle. Using friction modifiers in the ATF prevents this shudder.
http://www.bobistheoilguy.com/forums/ubb...ion#Post1111352
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Interesting how at the time George Zhang PhD stated Maxlife did not achieve the shear stability and low temperature performance requirements of Mercon V, yet Thom Smith, their then technical director, signed off that Valvoline supported the use of Maxlife in Mercon V applications.
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