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Frictional Response of Automatic Transmission Fluids in Band and Disc Clutches
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Abstract
The frictional response of automatic transmission fluids (ATF) in band clutches is significantly different from that in disc clutches. A research program was undertaken to investigate these differences and to explore effects of ATF chemistry on frictional response. Two disc clutch tests (the HEFCAD and the MERCON ® friction durability procedures), as well as two band tests (the THM 700-R4 and the 125C), were run on different fluids. Vehicle shift-feel tests were also run to better gauge the results.
It was found that the band tests yielded high static friction relative to dynamic friction whereas the disc clutch test results frequently gave the reverse. The static-minus-dynamic value (S-D), as measured in some of these bench tests, appears to predict the shift quality of a given fluid. Fluids based on sulfur-phosphorus (S-P) chemistry seem to bridge the gap between the disc clutch and band clutch friction better than fluids based on ZDDP chemistry.
The findings are believed to be helpful to the formulators of DEXRON® -III ATF 's. (DEXRON® -III is a future specification intended for a new generation of ATF for GM transmissions.)
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Citation
Papay, A. and Hartley, R., "Frictional Response of Automatic Transmission Fluids in Band and Disc Clutches," SAE Technical Paper 890721, 1989, https://doi.org/10.4271/890721.Also In
References
- Papay A.G. “Oil-Soluble Friction Reducers - Theory and Application.” Lubr. Eng. 39 7 419 426 1983
- Papay A.G. “Friction Reducers for Engine and Gear Oils - A Review of the State of the Art.” 5th International Colloquium: Additives for Lubricants and Operational Fluids 1 5.1-1 5.1-10 1986
- Grambo R.E. Dowell R.E. Mackay Ian “Oil-Immersed Static Coefficient of Friction-Definition and Methods of Determination,” SAE Paper 841065
- DEXRON ® -II Automatic Transmission Fluid Specification General Motors Corporation Second 1978.
- MERCON ® Automatic Transmission Fluid Specification Ford Motor Company 1987
- SAE Recommended Practices - J1499 February 1987: Band Friction Test Machine (SAE) Test Procedure, Revised February 1987
- Linden J.L. Kemp S.P. “Improving Transaxle Performance at Low Temperature with Reduced-Viscosity Automatic Transmission Fluids,” SAE Paper 870356
- Baule W.G. “Paper - A Unique Wet Clutch Friction Material,” Borg-Warner Corporation Bellwood, Illinois 1962
- Nakata H. Moroto S. Kobayashi K. “Prediction of the Life of Friction Material and Shift Quality of an Automatic Transmission,” SAE Paper 860385
- Watts R.F. Sparrow S.D. “Development of a THM 700-R4 Band Friction Test for the SAE No. 2 Machine,” SAE Paper 881675