Transfer Case - NV243: Other Dodge Pickup R2500

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.

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(tm) all purpose cleaner. Use compressed air to remove solvent residue from oil feed passages in the case halves, retainers, gears, and shafts.

INPUT GEAR AND PLANETARY CARRIER

Check the teeth on the gear (Scheme 283) Minor nicks can be dressed off with an oilstone but replace the gear if any teeth are broken, cracked, or chipped. The bearing surface on the gear can be smoothed with 300-400 grit emery cloth if necessary.

Scheme 283

Examine the carrier body and pinion gears for wear or damage. The carrier will have to be replaced as an assembly if the body, pinion pins, or pinion gears are damaged.

Check the lock ring and both thrust washers for wear or cracks. Replace them if necessary. Also replace the lock retaining ring if bent, distorted, or broken.

SHIFT FORKS/HUBS/SLEEVES

Check condition of the shift forks and mode fork shift rail (Scheme 284) Minor nicks on the shift rail can be smoothed with 320-400 grit emery cloth.

Scheme 284

Inspect the shift fork wear pads (Scheme 285) The mode and range fork pads are serviceable and can be replaced if necessary.

Scheme 285

Check both of the sleeves for wear or damage, especially on the interior teeth. Replace the sleeves if wear or damage is evident.

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.

LOW RANGE ANNULUS GEAR

Inspect annulus gear condition carefully. The gear is only serviced as part of the front case. 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 (Scheme 286)

Scheme 286

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(tm) 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(R) 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 287

Scheme 288

Scheme 289

Scheme 290

Scheme 291

Scheme 292

Scheme 293

Scheme 294

1. Remove the input shaft bearing (Scheme 287) from the front case with suitable snap-ring pliers.
2. Transfer the retaining ring to the new bearing if necessary and install the bearing into the front case.
3. Using Installer 6436 and Handle C-4171 (Scheme 288), remove front output shaft bearing.
4. Start front output shaft bearing in case. Then seat bearing with Handle C-4171 and Installer 6953.
5. Install front output shaft bearing retaining ring.
6. Remove input gear pilot bearing by inserting a suitably sized drift into the splined end of the input gear and driving the bearing out with the drift and a hammer (Scheme 289)
7. Install new pilot bearing with Remover/Installer 8684.
8. Remove the front output shaft rear bearing with the screw and jaws from Remover L-4454 and Cup 8148 (Scheme 290)
9. Install new bearing with Tool Handle C-4171 and Installer 5066 (Scheme 291) The bearing bore is chamfered at the top. Install the bearing so it is flush with the lower edge of this chamfer (Scheme 292)
10. Remove the rear output shaft bearing from the rear case using Remover/Installer 8684 and Handle C-4171 (Scheme 293)
11. Install the rear output shaft bearing (Scheme 294) into the rear case using Remover/Installer 6953 and Handle C-4171.

Scheme 295

Scheme 296

Scheme 297

1. Lubricate gears and thrust washers (Scheme 295) with recommended transmission fluid.
2. Install first thrust washer in low range gear (Scheme 295) Be sure washer tabs are properly aligned in gear notches.
3. Install input gear in low range gear. Be sure input gear is fully seated.
4. Install remaining thrust washer in low range gear and on top of input gear. Be sure washer tabs are properly aligned in gear notches.
5. Install retainer on input gear and install snap-ring.
6. Align and install low range/input gear assembly in front case (Scheme 296) Be sure low range gear pinions are engaged in annulus gear and that input gear shaft is fully seated in front bearing.
7. Install snap-ring to hold input/low range gear into front bearing (Scheme 297)
8. Install a new input gear seal using Installer 8841 and Handle C-4171.

Scheme 298

Scheme 299

Scheme 300

Scheme 301

Scheme 302

Scheme 303

Scheme 304

Scheme 305

Scheme 306

Scheme 307

Scheme 308

Scheme 309

Scheme 310

1. Lubricate mainshaft splines with recommended transmission fluid.
2. Install the mode hub (Scheme 298) onto the output shaft.
3. Install the mode hub retaining ring (Scheme 299) onto the output shaft.
4. Install the sprocket hub (Scheme 300) onto the output shaft.
5. Install the clutch gear (Scheme 301) onto the output shaft.
6. Install the drive sprocket (Scheme 302) onto the output shaft.
7. Install the drive sprocket thrust washer (Scheme 303) onto the output shaft.
8. Install the drive sprocket retaining ring (Scheme 304) onto the output shaft.
9. Lubricate sector shaft with transmission fluid and install shift sector in case (Scheme 305) Position slot in sector so it will be aligned with shift fork pin when shift forks are installed.
10. Install the shift sector o-ring.
11. Assemble and install range fork and hub (Scheme 306) 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.
14. Install mode fork and shift rail onto the mode sleeve.
15. Install the mode fork, sleeve, and shift rail into the transfer case (Scheme 307)
16. Install mainshaft into the transfer case (Scheme 308) Guide mainshaft through the mode and range sleeves and into the input gear.
17. Install new o-ring on detent plug (Scheme 309)
18. Install detent plunger, spring, and plug (Scheme 310) Tighten the plug to 16-25 N.m (12-18 ft. lbs.).

Scheme 311

Scheme 312

Scheme 313

Scheme 314

Scheme 315

Scheme 316

1. Install the front output shaft (Scheme 311) into the front output shaft bearing.
2. Install the front output shaft retaining ring (Scheme 312) onto the output shaft.
3. Install the new front output shaft seal with Installer MB991168A
4. Insert front sprocket in drive chain.
5. Install drive chain around mainshaft sprocket (Scheme 313) Then position front sprocket over front shaft.
6. Raise mainshaft about 2.54 cm (one inch) and seat front sprocket on front output shaft.
7. If mainshaft and mode sleeve were unseated during chain installation, align and reset mainshaft in input gear and hub.
8. Install front sprocket retaining ring (Scheme 314)
9. Install spring and cup on shift rail (Scheme 315)
10. Insert magnet in front case pocket (Scheme 316)

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.

Scheme 317

Scheme 318

Scheme 319

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(R) 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 and oil pump assembly (Scheme 317)
5. Install 4-5 rear case-to front case bolts (Scheme 318) 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(tm) 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.).
7. Install rear output bearing snap-ring (Scheme 319) to output shaft.