Shift Feel & ATF Fluid
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Shift Feel & ATF Fluid This is just a curiosity but has anyone ever noticed different trans fluids causing different shifting behaviors? Dex III vs VI for example, any noticeable differences in shifts? I believe the Dex III is a little thicker than the VI. I also believe I read that Valvoline’s Maxlife ATF is a little thinner than Dex VI for whatever that’s worth. Does the minute difference in viscosity make a difference?
Back when people would use Type F or B&M Trick Shift, what was that doing for guys? Harder shifts? If so, is that because Type F doesn’t have any friction modifiers?
Does the type of ATF play a very big roll in a transmissions behavior aside for tearing it up due to using the wrong fluid?
Back when people would use Type F or B&M Trick Shift, what was that doing for guys? Harder shifts? If so, is that because Type F doesn’t have any friction modifiers?
Does the type of ATF play a very big roll in a transmissions behavior aside for tearing it up due to using the wrong fluid?
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From: Iowa
Some will claim a "harder" shift with type F than others.
Yes it has no friction modifiers
Realistically, and I've posted this multiple times in the past
You want the fluid to do a handful of things
-anti-foam
-temperature stability
-bushing/bearing protection
Type F is garbage at all 3
Dex VI is pretty good at all 3
If you want a shift firmness change do it the right way. With electronically controlled transmissions you can do it a couple different "right ways"
Mechanically with orifice sizing or accumulator changes...or in the tune with pressure manipulation
Yes it has no friction modifiers
Realistically, and I've posted this multiple times in the past
You want the fluid to do a handful of things
-anti-foam
-temperature stability
-bushing/bearing protection
Type F is garbage at all 3
Dex VI is pretty good at all 3
If you want a shift firmness change do it the right way. With electronically controlled transmissions you can do it a couple different "right ways"
Mechanically with orifice sizing or accumulator changes...or in the tune with pressure manipulation
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Having discussions with the engineers at Borg Warner and Raybestos many many years ago. I asked the questions about type "F" and Dexron type oils. Type "F" was recommended when they were still using Asbestos in clutch material, mainly Ford & Chrysler. Asbestos was not used after 1978. Back then Asbestos was known a performance or a heavy duty type of clutch, and was recommended over paper type clutches at that time. Type "F" was recommended when using these type of clutches. When using type "F" in a (paper type clutch) transmission. You will cause the clutches to slip more at the start of the shift, and the clutches to come on all at once at the end of the shift. This is known as a "tail up" shift. This gives the feel of the shift being firmer. When in reality, it is harder on the splines in the transmission. Dexron type oils have the clutches starting to come on near the beginning of the shift, and throughout the shift. This gives the feel of the shift being smoother. As for holding power. The type "F" oil has a higher "static" holding power (forward and reverse clutches or band). Where the Dexron type oil has a higher "dynamic" holding power (any clutch or band that applies during a shift). Rarely do we see the forward clutches not holding. Since that time, we see Dexron type of oils improving every two to three years. There were transmissions in the distant past that did require type "F" oil and would not work with Dexron type of oil. Borg Warner model 35 comes to mind...
