Dodge RAM 1500 1998 Owner's Manual page 1857

21 - 154 AUTOMATIC TRANSMISSION - 48RE
AUTOMATIC TRANSMISSION - 48RE (Continued)
CONDITION
NO 3-4 UPSHIFT
POSSIBLE CAUSES
1. O/D Switch In OFF Position.
2. Overdrive Circuit Fuse Blown.
3. O/D Switch Wire Shorted/Open
Cut.
4. Distance or Coolant Sensor
Malfunction.
5. TPS Malfunction.
6. Neutral Sense to PCM Wire
Shorted/Cut.
7. PCM Malfunction.
8. Overdrive Solenoid Shorted/Open.
9. Solenoid Feed Orifice in Valve
Body Blocked.
10. Overdrive Clutch Failed.
11. Hydraulic Pressure Low.
12. Valve Body Valve Stuck.
13. O/D Piston Incorrect Spacer.
14. Overdrive Piston Seal Failure.
15. O/D Check Valve/Orifice Failed.
CORRECTION
1. Turn control switch to ON position.
2. Replace fuse. Determine why fuse failed
and repair as necessary (i.e., shorts or
grounds in circuit).
3. Check wires/connections with 12V test
lamp and voltmeter. Repair damaged or
loose wire/connection as necessary.
4. Check with DRB scan tool and repair or
replace as necessary.
5. Check with DRB scan tool and replace
if necessary.
6. Test switch/sensor as described in
service section and replace if necessary.
Engine no start.
7. Check with DRB scan tool and replace
if necessary.
8. Replace solenoid if shorted or open and
repair loose or damaged wires (DRB scan
tool).
9. Remove, disassemble, and clean valve
body thoroughly. Check feed orifice.
10. Disassemble overdrive and repair as
needed.
11. Pressure test transmission to determine
cause.
12. Repair stuck 3-4 shift valve, 3-4 timing
valve.
13. Remove unit, check end play and install
correct spacer.
14. Replace both seals.
15. Check for free movement and secure
assembly (in piston retainer). Check ball
bleed orifice.
DR