Pressure Testing

[mark65]

I am still having the problem with the 1-2 upshift on my 2000 f150 with the 4r70w. I did a pressure test today. The pressures at the line and intermediate cutch taps were within specs, But I did notice something when the intermediate clutch is applied. The pressure would start off at 0 and slowly rise. Once it got to around 40-50psi it would quickly rise to over 80 psi and that is when I would feel the bang. When a shift is commanded, is the pressure supposed to rise instanteously, or should it gradually rise? The pressure dropped down to 0 very quickly on the downshifts into 1st. Do you think the shift solenoid is not opening fast enough?

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[Drdexron]

Have you checked your 1-2 accumulator piston and springs?

[mark65]

Yes I have already checked the 1-2 accumulator. The springs were not broken.

[Drdexron]

The slow rise in pressure is the effect of the 1-2 accumulator. That's how the transmission controls the application of the intermediate clutches.