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CHRYSLER A604 - Delayed Engagement And/Or Harsh Coast Downshift

Posted on by Amos

COMPLAINT: Delayed engagement both in forward and reverse and/or, harsh 2-1 coast downshift and/or, slips and bangs after stopping quickly and/or, 3-1 kickdown runaway with a bang at the end and/or, defaults to limp mode when hot.

CAUSE: The cause may be, a leaking gasket between the low/reverse piston retainer and the case.

QUALIFICATION:
(1) Scan the transaxle controller for any stored fault codes, record the codes and then erase fault codes from the controllers memory.
(2) Attach a 0-300 pound pressure gauge on the low/reverse clutch pressure tap. Record the pressures seen with the engine at idle in Park, Reverse, Neutral and Drive while the vehicle is standing still.
(3) Road test the vehicle with the pressure gauge still attached to the low/reverse pressure tap. While you are driving the vehicle in 2nd, 3rd, or 4th gear, the pressure gauge should read zero. Coast down to gentle stop and "OBSERVE" the pressure gauge carefully. Usually the pressure will begin to rise just before the transaxle downshifts to first gear. The pressure will be low and will usually boost up when the bang occurs. During a 3-1 kick down, the pressure will often respond in the same manner.

CORRECTION: Replace the low/reverse clutch piston retainer gasket, as shown in Figure 1. Install a new design low/reverse clutch retainer, OEM part number 4431648, and use Locktite on the three retaining bolts. Install a new design low/reverse piston, OEM part number 4431672, which prevents the possibility of thermal bind-up in the piston retainer. The new design piston is .002" smaller on the outside diameter above the lip seal. You can machine your original piston. by reducing the overall outside diameter by .002" in the area shown in Figure 3.

SERVICE INFORMATION:
Low/Reverse Clutch Piston Retainer (New Design) ................................................. 4431648
Low/Reverse Clutch Piston (New Design) ............................................................... 4431672

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CHRYSLER A604 - Delayed Engagement And/Or Harsh Coast Downshift
CHRYSLER A604 - Delayed Engagement And/Or Harsh Coast Downshift

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