NV243 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 Drive Train Control Module (DTCM) to indicate the driver's desire to change operating ranges. The DTCM 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 DTCM decides the shift is permitted, the DTCM controls the shift motor, mounted to the exterior of the transfer case, to perform the shift.

Scheme 48

A circular ID tag (1) is attached to the rear case of each transfer case. (Scheme 48) 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 49

Inspect annulus gear (2) condition carefully. (Scheme 49) 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 50

Scheme 51

Scheme 52

Scheme 53

Scheme 54

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Scheme 56

Scheme 57

1. Remove the input shaft bearing (1) from the front case (2) with suitable snap-ring pliers.
2. Transfer the retaining ring to the new bearing if necessary and install the bearing into the front case. 1 - FRONT CASE 2 - BEARING INSTALLER 6436 3 - UNIVERSAL HANDLE C-4171
3. Using Bearing Installer (special tool #6436, Installer, Bearing) (2) and Universal Handle (special tool #C-4171, Driver Handle, Universal) (3), remove front output shaft bearing.
4. Start front output shaft bearing in case. Then seat bearing with Universal Handle (special tool #C-4171, Driver Handle, Universal) and Bearing Remover/Installer (special tool #6953, Remover/Installer, Bearing).
5. Install front output shaft bearing retaining ring. 1 - DRIFT 2 - INPUT GEAR
6. Remove input gear (2) pilot bearing by inserting a suitably sized drift (1) into the splined end of the input gear and driving the bearing out with the drift and a hammer.
7. Install new pilot bearing with Bearing Installer (special tool #8684, Installer, Bearing). 1 - REAR CASE 2 - REMOVER L-4454-1 AND L-4454-3 3 - CUP 8148
8. 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). 1 - UNIVERSAL HANDLE C-4171 2 - OUTPUT SHAFT INNER BEARING 3 - BUSHING INSTALLER 5066
9. Install new bearing with Universal Handle (special tool #C-4171, Driver Handle, Universal) and Bushing Installer (special tool #5066, Installer, Bushing). 1 - BEARING (SEATED) AT LOWER EDGE OF CHAMFER 2 - CHAMFER
10. The bearing bore is chamfered at the top. Install the bearing (1) so it is flush with the lower edge of this chamfer (2). 1 - REAR CASE 2 - BEARING INSTALLER 8684 3 - UNIVERSAL HANDLE C-4171
11. Remove the rear output shaft bearing from the rear case (1) using Bearing Installer (special tool #8684, Installer, Bearing) (2) and Universal Handle (special tool #C-4171, Driver Handle, Universal) (3). 1 - REAR CASE 2 - BEARING REMOVER/INSTALLER 6953 3 - UNIVERSAL HANDLE C-4171
12. Install the rear output shaft bearing into the rear case (1) using Bearing Remover/Installer (special tool #6953, Remover/Installer, Bearing) (2) and Universal Handle (special tool #C-4171, Driver Handle, Universal) (3).

Scheme 58

1. Lubricate gears (4) and thrust washers (5) with recommended transmission fluid.
2. Install first thrust washer in low range gear (5). Be sure washer tabs are properly aligned in gear notches.
3. Install input gear (3) in low range gear (4). Be sure input gear is fully seated.
4. Install remaining thrust washer (5) in low range gear (4) and on top of input gear (3). Be sure washer tabs are properly aligned in gear notches.
5. Install retainer (2) on input gear and install snap-ring (1). 1 - FRONT CASE 2 - INPUT PLANETARY ASSEMBLY
6. Align and install low range/input gear assembly (2) in front case (1). 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
7. Install snap-ring (2) to hold input/low range gear (1) into front bearing.
8. Install a new input gear seal using Installer (special tool #8841, Installer, Seal) and Universal Handle (special tool #C-4171, Driver Handle, Universal).

SHIFT FORKS AND MAINSHAFT

Scheme 59

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Scheme 61

1. Lubricate mainshaft splines with recommended transmission fluid.
2. Install the mode hub (2) onto the output shaft (1). 1 - OUTPUT SHAFT 2 - RETAINING RING 3 - MODE HUB
3. Install the mode hub retaining ring (2) onto the output shaft (1). 1 - OUTPUT SHAFT 2 - SPROCKET HUB
4. Install the sprocket hub (2) onto the output shaft (1). 1 - OUTPUT SHAFT 2 - CLUTCH GEAR 3 - MODE HUB
5. Install the clutch gear (2) onto the output shaft (1). 1 - OUTPUT SHAFT 2 - DRIVE SPROCKET
6. Install the drive sprocket (2) onto the output shaft (1). 1 - OUTPUT SHAFT 2 - THRUST WASHER 3 - DRIVE SPROCKET
7. Install the drive sprocket (3) thrust washer (2) onto the output shaft (1). 1 - OUTPUT SHAFT 2 - RETAINING RING 3 - DRIVE SPROCKET
8. Install the drive sprocket (3) retaining ring (2) onto the output shaft (1). 1 - SHIFT SECTOR
9. Lubricate sector shaft (1) with transmission fluid and install shift sector in case. Position slot in sector so it will be aligned with shift fork pin when shift forks are installed. 1 - RANGE HUB 2 - RANGE FORK
10. Install the shift sector o-ring.
11. Assemble and install range fork (2) and hub (1). Be sure hub is properly seated in low range gear and engaged to the input gear.
12. Align and insert range fork pin in shift sector slot.
13. Install the range fork retaining ring. 1 - MODE SLEEVE 2 - MODE FORK AND RAIL
14. Install mode fork and shift rail onto the mode sleeve.
15. Install the mode fork (2), sleeve (1), and shift rail (2) into the transfer case. 1 - FRONT CASE 2 - MAINSHAFT
16. Install mainshaft (2) into the transfer case front housing (1). Guide mainshaft through the mode and range sleeves and into the input gear. 1 - O-RING 2 - DETENT PLUG
17. Install new o-ring (1) on detent plug (2). 1 - FRONT CASE 2 - DETENT PLUG 3 - DETENT SPRING 4 - DETENT PLUNGER
18. Install detent plunger (4), spring (3), and plug (2). Tighten the plug to 16-24 N.m (12-18 ft. lbs.).

Scheme 62

Scheme 63

Scheme 64

1. Install the front output shaft (2) into the front output shaft bearing. 1 - FRONT OUTPUT SHAFT 2 - SNAP-RING
2. Install the front output shaft retaining ring (2) onto the output shaft (1).
3. Install the new front output shaft seal with Seal Installer (special tool #MB-991168-A, Installer, Seal). 1 - FRONT DRIVE SPROCKET 2 - DRIVE CHAIN 3 - MAINSHAFT
4. Insert front sprocket (1) in drive chain (2).
5. Install drive chain (2) around mainshaft sprocket. Then position front sprocket over front shaft.
6. Raise mainshaft about 2.54 cm (one inch) and seat front sprocket on front output shaft. 1 - FRONT SPROCKET 2 - RETAINING RING
7. If mainshaft and mode sleeve were unseated during chain installation, align and reseat mainshaft in input gear and hub.
8. Install front sprocket (1) retaining ring (2). 1 - CUP 2 - SPRING
9. Install spring (2) and cup (1) on shift rail. 1 - MAGNET 2 - CASE POCKET
10. Insert magnet (1) in front case pocket (2).

OIL PUMP AND REAR CASE

Lubricate the oil pump components with transmission fluid before installation. Prime the oil pickup tube by pouring a little oil into the tube before installation.

1. Install new o-ring in pickup tube inlet of oil pump.
2. Insert oil pickup tube into the oil pump.
3. 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.
4. Align oil pump with mainshaft and align shift rail with bore in rear case. Then install rear case (1) and oil pump assembly onto the front case (2). see scheme 73 1 - REAR CASE 2 - FRONT CASE 3 - BOLT
5. Install 4-5 rear case (1)-to front case (2) bolts (3) to hold rear case in position. 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.
6. Apply Loctite© 242 to remainder of rear case-to-front case bolt threads and install bolts. Tighten bolts to 20-27 N.m (15-24 ft. lbs.). 1 - REAR OUTPUT SHAFT 2 - OUTPUT SHAFT BEARING 3 - RETAINING RING 4 - TRANSFER CASE
7. Install rear output bearing (2) snap-ring (3) to output shaft (1).

REAR EXTENSION

1. Install new seal in rear extension housing seal with Installer (special tool #D-163, Installer, Seal) and Universal Handle (special tool #C-4171, Driver Handle, Universal).
2. 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.
3. Align and install rear extension (1) on the transfer case (2).
4. Apply Mopar® Silicone Sealer to threads of rear extension housing bolts. Then install and tighten bolts to 16-24 N.m (12-18 ft. lbs.) torque.