Gear Shift Performance

SYMPTOM/CONDITION/DIAGNOSIS

GEAR SHIFT PERFORMANCE

COLD WEATHER SHIFT PERFORMANCE (AMBIENT TEMPERATURE BELOW 30~F/-1~C. Two basic gear shift conditions can relate to cold weather operation.

^ High shift efforts are experienced after a cold soak at temperatures below 30~F (-1~C). Reduced shift efforts are experienced after the transmission reaches operating temperature. The increased effort is caused by an increase of the transmission lubricant (lOW30 engine oil) viscosity. A change to Dexron II Automatic Transmission Fluid, PN 4467721 will reduce the cold weather shift effort. The use of ATF will not sacrifice transmission durability. Refer to Technical Service Bulletin # 21-27-89 Rev.A, Dated December 22, 1989 for additional information.

^ Transmission slips out of gear after a cold soak at temperatures below 32~F (O~C). This condition may occur statically with the clutch pedal depressed and/or dynamically when no driveline torque is being transmitted. This condition is the result of the shift lever boot material stiffening at low temperatures and exerting a pulling effort on the shift lever. This condition can be corrected by installing new detent springs PN 53006659. Refer to Technical Service Bulletin # 21-11-89, Dated May 8, 1989 for repair procedure.

NOTE: THE NEW DETENT SPRINGS ENTERED TRANSMISSION PRODUCTION ON TRANSMISSION BUILD DATE CODE 11-24-88

HIGH SHIFTING EFFORT OR GEAR CLASHING DURING NORMAL OPERATION High shift effort or gear clashing during normal vehicle operation can be caused by clutch system or transmission problems. Before performing any transmission repairs it is important the clutch system be inspected for proper operation. This inspection should include:

Clutch master cylinder fluid level. Slave cylinder operation. Pedal linkage. Transmission lubricant level. Clutch disc "spin down time" test. * Clutch housing alignment. Clutch spline lubrication. Clutch disc runout.
* Spin down time is the time required for the clutch disc to stop rotating when the clutch pedal is completely depressed. A spin down time in excess of five seconds may be caused by lack of lubrication of the clutch splines and or pilot bushing, clutch housing misalignment, or excessive clutch disc runout. To check spin down time perform the following procedure:

NOTE: THIS PROCEDURE SHOULD BE PERFORMED ON A LEVEL SURFACE, DO NOT SET THE PARKING BRAKE.

1. Check transmission lubricant level.(Low lubricant can cause excessive spin down time).

2. Shift the transmission into neutral. Start the engine. Completely depress the clutch pedal. Count to five and shift the transmission into reverse. If no high effort or clashing is experienced, repeat the procedure counting to three before shifting into reverse.

If high effort or clashing was experienced perform the procedures outlined in Technical Service Bulletins 06-01-89, Dated January 16, 1989, Clutch Splines/Pilot Bushing Lubrication and 06-03-89, Dated June 12, 1989, Clutch Housing, Pilot Bore Face Squareness Adjustment.

Check clutch disc runout per the procedure outlined on page 6-11 in the 1990 Dakota Rear Wheel Drive Truck Service Manual, Publication # 81-370-0110. Clutch disc runout must be less than .020 inch (0.5 mm). If runout is .020 or more replace the clutch disc.

If no high effort or clashing was experienced within the three to five second spin down test, but was experienced during the road test the clutch housing alignment and clutch disc runout should be checked before disassembling the transmission. If the clutch housing alignment and clutch disc runout are found to be within specifications the synchronizer and shifting systems must be inspected per the procedure outlined on pages 7 and 8 of this bulletin.