NV273 Transfer Case - Service Information: Other RAM Pickup 2500

OPERATING RANGES

Transfer case operating ranges are

1. 2WD (2-wheel drive).
2. 4HI (4-wheel drive).
3. 4LO (4-wheel drive low range).
4. NEUTRAL.

The 2WD range is for use on any road surface at any time.

The 4HI and 4LO ranges are for off road use only. They are not for use on hard surface roads. The only exception being when the road surface is wet or slippery or covered by ice and snow.

The low range reduction gear system is operative in 4LO range only. This range is for extra pulling power in off road situations. Low range reduction ratio is 2.72:1.

SHIFT MECHANISM

Operating ranges are selected with a dash mounted shift selector switch. The shift selector switch provides a input to the Transfer Case Control Module (TCCM) to indicate the driver's desire to change operating ranges. The TCCM uses this input, along with input from the transfer case mounted mode sensor and information from the vehicle's bus, to determine if a shift is permitted. If the TCCM decides the shift is permitted, the TCCM controls the shift motor, mounted to the exterior of the transfer case, to perform the shift.

Scheme 181

A circular ID tag (2) is attached to the rear case of each transfer case. The ID tag provides the transfer case model number, assembly number, serial number, and low range ratio.

The transfer case serial number also represents the date of build.

CLEANING

Clean the transfer case parts with a standard parts cleaning solvent. Remove all traces of sealer from the cases and retainers with a scraper and 3M© all purpose cleaner. Use compressed air to remove solvent residue from oil feed passages in the case halves, retainers, gears, and shafts.

REAR EXTENSION HOUSING

Inspect the extension housing seal and bushing. Replace both components if either show any sign of wear or damage.

FRONT OUTPUT SHAFT AND DRIVE CHAIN

Inspect the shaft threads, sprocket teeth, and bearing surfaces. Minor nicks on the teeth can be smoothed with an oilstone. Use 320-400 grit emery to smooth minor scratches on the shaft bearing surfaces. Rough threads on the shaft can be chased if necessary. Replace the shaft if the threads are damaged, bearing surfaces are scored, or if any sprocket teeth are cracked or broken.

Examine the drive chain and shaft bearings. Replace the chain and both sprockets if the chain is stretched, distorted, or if any of the links bind. Replace the bearings if rough, or noisy.

Scheme 182

Inspect annulus gear (2) condition carefully. (Scheme 182) The gear is only serviced as part of the front case (1). If the gear is damaged, it will be necessary to replace the gear and front case as an assembly. Do not attempt to remove the gear.

FRONT AND REAR CASES

Inspect the cases for wear and damage.

Check case condition. If leaks were a problem, look for gouges and severe scoring of case sealing surfaces. Also make sure the front case mounting studs are in good condition.

Check the front case mounting studs and vent tube. The tube can be secured with Loctite© 271 or 680 if loose. The stud threads can be cleaned up with a die if necessary. Also check condition of the fill/drain plug threads in the rear case. The threads can be repaired with a thread chaser or tap if necessary. Or the threads can be repaired with Helicoil® stainless steel inserts if required.

OIL PUMP/OIL PICKUP

Examine the oil pump pickup parts. Replace the pump if any part appears to be worn or damaged. Do not disassemble the pump as individual parts are not available. The pump is only available as a complete assembly. The pickup screen, hose, and tube are the only serviceable parts and are available separately.

Scheme 183

Scheme 184

Scheme 185

Scheme 186

Scheme 187

Scheme 188

Scheme 189

Scheme 190

Scheme 191

Scheme 192

Scheme 193

Scheme 194

1. Remove the input shaft bearing snap-ring from the front case half with suitable snap-ring pliers.
2. Remove the input shaft bearing from the front case half with Bearing Remover/Installer (special tool #6953, Remover/Installer, Bearing) (3) and Universal Handle (special tool #C-4171, Driver Handle, Universal) (2). (Scheme 183) 1 - FRONT CASE HALF 2 - UNIVERSAL HANDLE C-4171 3 - BEARING CUP INSTALLER 8151 (INVERTED)
3. Install the input shaft bearing into the front case half with Bearing Cup Installer (special tool #8151, Installer, Bearing Cup) (3) inverted on Universal Handle (special tool #C-4171, Driver Handle, Universal) (2). (Scheme 184)
4. Install the input shaft bearing snap-ring into the front case half with suitable snap-ring pliers. 1 - FRONT CASE HALF 2 - UNIVERSAL HANDLE C-4171 3 - BEARING INSTALLER 6953
5. Remove the front output shaft front bearing snap-ring from the front case half.
6. Using Bearing Remover/Installer (special tool #6953, Remover/Installer, Bearing) (3) and Universal Handle (special tool #C-4171, Driver Handle, Universal) (2), remove the front output shaft front bearing. (Scheme 185) 1 - FRONT CASE HALF 2 - SEAL INSTALLER 8891
7. Start front output shaft front bearing in case. Then seat bearing with Seal Installer (special tool #8891, Installer, Seal) (2). (Scheme 186)
8. Install front output shaft bearing retaining ring. 1 - DRIFT 2 - INPUT GEAR
9. Remove input gear pilot bearing by inserting a suitably sized drift (1) into the splined end of the input gear (2) and driving the bearing out with the drift and a hammer. (Scheme 187)
10. Install new pilot bearing with Pilot Bearing Installer (special tool #9035, Installer, Bearing). 1 - REAR CASE 2 - REMOVER L-4454-1 AND L-4454-3 3 - CUP 8148
11. Remove the front output shaft rear bearing with the screw and jaws from Remover (special tool #L-4454A, Remover, Bearing Cup) (2) and Cup (special tool #8148, Cup) (3). (Scheme 188) 1 - REAR CASE HALF 2 - UNIVERSAL HANDLE C-4171 3 - BEARING INSTALLER 8128
12. Install new bearing with Universal Handle (special tool #C-4171, Driver Handle, Universal) (2) and Bearing Installer (special tool #8128, Installer, Bearing) (3). (Scheme 189) 1 - BEARING (SEATED) AT LOWER EDGE OF CHAMFER 2 - CHAMFER
13. The bearing bore is chamfered at the top. Install the bearing so it is flush (1) with the lower edge of this chamfer (2). (Scheme 190) 1 - HOUSING SEAL 2 - SEAL INSTALLER 7888 3 - OIL PUMP FEED HOUSING
14. Remove seal from oil pump with suitable pry tool.
15. Install new seal in oil pump with Seal Installer (special tool #7888, Installer, Seal) (2). (Scheme 191) 1 - REAR CASE HALF 2 - REAR OUTPUT SHAFT BEARING 3 - SNAP-RING
16. Remove the rear output shaft bearing (2) snap-ring (3) from the rear case half (1). (Scheme 192) 1 - REAR CASE HALF 2 - SEAL INSTALLER 7888
17. Remove the rear output shaft bearing from the rear case (1) using Seal Installer (special tool #7888, Installer, Seal) (2). (Scheme 193) 1 - REAR CASE HALF 2 - UNIVERSAL HANDLE C-4171 3 - SEAL INSTALLER 8152
18. Install the rear output shaft bearing into the rear case (1) using Seal Installer (special tool #8152, Installer, Seal) (3) and Universal Handle (special tool #C-4171, Driver Handle, Universal) (2). (Scheme 194)
19. Install the rear output shaft bearing snap-ring into the rear case half.

INPUT AND PLANETARY GEAR

1. Lubricate gears and thrust washers with recommended transmission fluid.
2. Install bottom thrust washer (2) in low range gear planetary (1). see scheme 55 Be sure washer tabs are properly aligned in gear notches. 1 - INPUT GEAR 2 - LOW RANGE PLANETARY
3. Install input gear (1) in low range gear (2). see scheme 56 Be sure input gear is fully seated. 1 - INPUT GEAR 2 - THRUST PLATE
4. Install remaining thrust washer (2) in low range gear and on top of input gear (1). see scheme 57 1 - INPUT GEAR 2 - RETAINER
5. Install retainer (2) on input gear (1). see scheme 58 1 - INPUT GEAR 2 - RETAINING RING
6. Install snap-ring (2). see scheme 59 1 - FRONT CASE 2 - INPUT PLANETARY ASSEMBLY
7. Align and install low range/input gear assembly (2) in front case (1). see scheme 60 Be sure low range gear pinions are engaged in annulus gear and that input gear shaft is fully seated in front bearing. 1 - INPUT GEAR 2 - RETAINING RING
8. Install snap-ring (2) to hold input/low range gear (1) into front bearing. see scheme 61
9. Install a new input gear oil seal with Seal Installer (special tool #9036, Installer, Seal) and Universal Handle (special tool #C-4171, Driver Handle, Universal).

SHIFT FORKS AND MAINSHAFT

Scheme 195

Scheme 196

1. Lubricate mainshaft splines with recommended transmission fluid.
2. Coat the interior of the drive sprocket hub with ATF+4 and install the drive sprocket drive hub (2) onto the mainshaft (1). see scheme 62 1 - MAINSHAFT 2 - MODE HUB
3. Install the mode hub (2) onto the mainshaft (1). see scheme 63 1 - MAINSHAFT 2 - MODE HUB 3 - RETAINING RING
4. Install the mode hub (2) retaining ring (3) onto the mainshaft (1). see scheme 64 1 - OUTPUT SHAFT 2 - CLUTCH GEAR 3 - MODE HUB
5. Install the clutch gear (2) onto the output shaft (1). see scheme 65 Verify that the pointed ends of the clutch gear teeth are pointing to the front of the mainshaft. 1 - SHIFT SECTOR
6. Lubricate sector shaft with transmission fluid and install shift sector (1) in case. see scheme 66 Position slot in sector so it will be aligned with shift fork pin when shift forks are installed.
7. Apply Loctite© 242, or equivalent, to the threads of the sector support to replenish the factory applied patch. Install the shift sector support. Tighten the sector support with Socket (special tool #9033, Socket, Sector Support) to 27-34 N.m (20-25 ft. lbs.). 1 - RANGE HUB 2 - RANGE FORK
8. Assemble and install range fork (2) and hub (1). (Scheme 195) Be sure hub is properly seated in low range gear and engaged to the input gear.
9. Align and insert range fork pin in shift sector slot. 1 - MODE SLEEVE 2 - MODE FORK AND RAIL
10. Install mode fork and shift rail onto the mode sleeve.
11. Install the mode fork and sleeve (1), and shift rail (2) into the transfer case. 1 - O-RING 2 - DETENT PLUG
12. Install new o-ring (1) on detent plug (2). (Scheme 196) 1 - FRONT CASE HALF 2 - DETENT PLUG 3 - SPRING 4 - PLUNGER
13. Install detent plunger (4), spring (3), and plug (2). see scheme 70 Tighten the plug to 16-24 N.m (12-18 ft. lbs.). 1 - TRANSFER CASE 2 - SHIFT MOTOR ASSEMBLY
14. Position the shift motor and mode sensor assembly (2) onto the transfer case (1). see scheme 71 1 - TRANSFER CASE 2 - SHIFT MOTOR ASSEMBLY 3 - BOLTS
15. Install the bolts (3) to hold the shift motor and mode sensor assembly (2) to the transfer case (1). see scheme 72 Tighten the bolts to 16-25 N.m (12-18 ft. lbs.). 1 - FRONT CASE HALF 2 - MAINSHAFT ASSEMBLY
16. Install mainshaft (2) into the transfer case (1). see scheme 73 Guide mainshaft through the mode and range sleeves and into the input gear.

Scheme 197

1. Install the front output shaft (2) into the front output shaft front bearing. see scheme 74 1 - FRONT CASE HALF 2 - SNAP-RING
2. Install the front output shaft bearing inner snap-ring (2) onto the output shaft. see scheme 75
3. Install the new front output shaft seal with Seal Installer (special tool #MB-991168-A, Installer, Seal). 1 - FRONT CASE HALF 2 - CHAIN 3 - DRIVE SPROCKETS
4. Insert front drive sprocket (3) in drive chain (2). see scheme 76
5. Install drive chain around rear drive sprocket.
6. Position rear drive sprocket over the output shaft and lower the sprocket and chain assembly until the front sprocket is positioned over the front output shaft.
7. Align the splines in the sprockets to the splines on the output shafts and install the sprockets onto the output shafts. 1 - FRONT OUTPUT SHAFT 2 - DRIVE SPROCKET 3 - RETAINING RING
8. Install front sprocket (2) retaining ring (3). see scheme 77 1 - REAR OUTPUT SHAFT 2 - DRIVE SPROCKET 3 - RETAINING RING
9. Install rear sprocket (2) retaining ring (3). see scheme 78 1 - MAGNET 2 - CASE POCKET
10. Insert magnet (1) in front case pocket (2). (Scheme 197)

REAR CASE

1. Install the oil pick-up tube and screen into the rear case half.
2. Apply bead of Mopar® Gasket Maker, or equivalent, to mating surface of front case. Keep sealer bead width to maximum of 3/16 inch. Do not use excessive amount of sealer as excess will be displaced into case interior.
3. Align mainshaft with the rear output shaft bearing and align shift rail with bore in rear case. Then install rear case (2). see scheme 80 Verify that the case alignment dowels correctly seat into their mating recesses. 1 - FRONT CASE HALF 2 - REAR CASE HALF 3 - BOLTS
4. Install 4-5 rear case (2) to front case (1) bolts (3) to hold rear case in position. see scheme 81 Tighten bolts snug but not to specified torque at this time. CAUTION: Verify that shift rail, and case alignment dowels are seated before installing any bolts. Case could be cracked if shaft rail or dowels are misaligned.
5. Tighten bolts to 27-34 N.m (20-25 ft. lbs.). 1 - OUTPUT SHAFT 2 - REAR CASE HALF 3 - SNAP-RING
6. Install rear output bearing inner snap-ring (3) to output shaft (1). see scheme 82

OIL PUMP AND REAR EXTENSION

Scheme 198

1. Install the oil pump (3) onto the output shaft (2). see scheme 83 1 - OIL PUMP 2 - OIL PICK-UP TUBE
2. Engage the oil pump pick-up tube (2) into the oil pump (1). see scheme 84 Verify that the pick-up tube o-ring is on the tube and is correctly installed to the oil pump. 1 - REAR CASE HALF 2 - EXTENSION HOUSING
3. Apply bead of Mopar® Gasket Maker, or equivalent, to mating surface of rear extension housing. Keep sealer bead width to maximum of 3/16 inch. Do not use excessive amount of sealer as excess could be displaced into output bearing.
4. Install extension housing (2) onto the rear case half (1). see scheme 85 1 - EXTENSION HOUSING 2 - BOLTS
5. Install rear extension bolts (2). see scheme 86 Tighten the bolts to 27-34 N.m (20-25 ft. lbs.). 1 - EXTENSION HOUSING 2 - UNIVERSAL HANDLE C-4171 3 - SEAL INSTALLER 9037
6. Install the extension housing dust boot and seal assembly with Seal Installer (special tool #9037, Installer, Dust Boot/Seal) (3) and Universal Handle (special tool #C-4171, Driver Handle, Universal) (2). (Scheme 198) 1 - YOKE HOLDER 6719 2 - BOLTS
7. Install the front companion flange onto the front output shaft.
8. Install two bolts 180° apart into the front output shaft companion flange.
9. Place holder (1) over the bolts (2) and against the companion flange. see scheme 88
10. Install a new front companion flange nut. Tighten the companion flange nut to 176-271 N.m (130-200 ft. lbs.).