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Front Axle - C205FD: Other RAM Pickup 2500

Differentials & Drive Axles 21 illustrations ~1766 words

LOW SPEED KNOCK

Low speed knock is generally caused by

  1. Worn U-joints/CV joint.
  2. Worn side-gear thrust washers.
  3. Worn pinion shaft bore.

DRIVELINE SNAP

A snap or clunk noise when the vehicle is shifted into gear (or the clutch engaged) can be caused by

  1. High engine idle speed.
  2. Transmission shift operation.
  3. Loose engine/transmission/transfer case mounts.
  4. Worn U-joints/CV joint.
  5. Loose spring mounts.
  6. Loose pinion gear nut and yoke.
  7. Excessive ring gear backlash.
  8. Excessive side gear to case clearance.

The source of a snap or a clunk noise can be determined with the assistance of a helper. Raise the vehicle on a hoist with the wheels free to rotate. Instruct the helper to shift the transmission into gear and listen for the noise. A mechanics stethoscope is helpful in isolating the source of a noise.

ConditionPossible CausesCorrection
Wheel Noise1. Wheel loose.1. Tighten loose nuts.
2. Worn wheel bearing.2. Replace bearing.
Axle Shaft Noise1. Misaligned axle tube.1. Inspect axle tube alignment. Correct as necessary.
2. Bent or sprung axle shaft.2. Inspect and correct as necessary.
3. End-play in pinion bearings.3. Refer to pinion pre-load information and correct as necessary.
4. Excessive gear backlash between the ring gear and pinion.4. Check adjustment of the ring gear and pinion backlash. Correct as necessary.
5. Improper adjustment of pinion gear bearings.5. Adjust the pinion bearings pre-load.
6. Loose pinion yoke nut.6. Tighten the pinion yoke nut.
7. Scuffed gear tooth contact surfaces.7. Inspect and replace as necessary.
Axle Shaft Broke1. Misaligned axle tube.1. Replace the broken shaft after correcting tube mis-alignment.
2 Vehicle overloaded.2. Replace broken shaft and avoid excessive weight on vehicle.
3. Erratic clutch operation.3. Replace broken shaft and avoid or correct erratic clutch operation.
4. Grabbing clutch.4. Replace broken shaft and inspect and repair clutch as necessary.
Differential Cracked1. Improper adjustment of the differential bearings.1. Replace case and inspect gears and bearings for further damage. Set differential bearing pre-load properly.
2. Excessive ring gear backlash.2. Replace case and inspect gears and bearings for further damage. Set ring gear backlash properly.
3. Vehicle overloaded.3. Replace case and inspect gears and bearings for further damage. Avoid excessive vehicle weight.
4. Erratic clutch operation.4. Replace case and inspect gears and bearings for further damage. Avoid erratic use of clutch.
Differential Gears Scored1. Insufficient lubrication.1. Replace scored gears. Fill differential with the correct fluid type and quantity.
2. Improper grade of lubricant.2. Replace scored gears. Fill differential with the correct fluid type and quantity.
3. Excessive spinning of one wheel/tire.3. Replace scored gears. Inspect all gears, pinion bores, and shaft for damage. Service as necessary.
Loss Of Lubricant1. Lubricant level too high.1. Drain lubricant to the correct level.
2. Worn axle shaft seals.2. Replace seals.
3. Cracked differential housing.3. Repair as necessary.
4. Worn pinion seal.4. Replace seal.
5. Worn/scored yoke.5. Replace yoke and seal.
6. Axle cover not properly sealed.6. Remove, clean and seal cover.
Axle Overheating1. Lubricant level low.1. Fill differential to correct level.
2. Improper grade of lubricant.2. Fill differential with the correct fluid type and quantity.
3. Bearing pre-loads too high.3. Adjust bearing pre-loads.
4. Insufficient ring gear backlash.4. Adjust ring gear backlash.
Gear Teeth Broke1. Overloading.1. Replace gears. Examine other gears and bearings for possible damage.
2. Erratic clutch operation.2. Replace gears and examine the remaining parts for damage. Avoid erratic clutch operation.
3. Ice-spotted pavement.3. Replace gears and examine remaining parts for damage.
4. Improper adjustments.4. Replace gears and examine remaining parts for damage. Ensure ring gear backlash is correct.
Axle Noise1. Insufficient lubricant.1. Fill differential with the correct fluid type and quantity.
2. Improper ring gear and pinion adjustment.2. Check ring gear and pinion contact pattern.
3. Unmatched ring gear and pinion.3. Replace gears with a matched ring gear and pinion.
4. Worn teeth on ring gear and pinion.4. Replace ring gear and pinion.
5. Loose pinion bearings.5. Adjust pinion bearing pre-load.
6. Loose differential bearings.6. Adjust differential bearing pre-load.
7. Ring gear run-out.7. Measure ring gear run-out. Replace components as necessary.
8. Loose differential bearing cap bolts.8. Inspect differential components and replace as necessary. Ensure that the bearing caps are torqued tot he proper specification.
9. Housing not machined properly.9. Replace housing.

DIAGNOSTIC CHART

Scheme 303

Scheme 303: ADJUSTMENTS
Scheme 303: ADJUSTMENTS

Ring gear (3) and pinion are supplied as a matched sets. Identifying numbers for the ring gear and pinion are painted onto the pinion gear shaft and the side of the ring gear. A plus (+) number, minus (-) number or zero (0) along with the gear set sequence number (01 to 99) is on each gear. This first number is the amount (in thousandths of an inch) the depth varies from the standard depth setting of a pinion marked with a (0). The next two numbers are the sequence number of the gear set. Compensation for pinion depth variance is achieved with select shims (1) located between the rear pinion bearing cone and pinion gear head.

If installing a new gear, note the depth variance number of the original and replacement pinion. Add or subtract this number from the original depth shim/oil slinger to compensate for the difference in the depth variances. The numbers represent thousands of an inch deviation from the standard. If the number is negative, add that value to the required thickness of the depth shims. If the number is positive, subtract that value from the thickness of the depth shim.

Pinion Gear Depth Variance Chart : Note where Old and New Pinion Marking columns intersect. Intersecting figure represents plus or minus the amount needed.

Original Pinion Gear Depth VarianceNew Pinion Gear Depth Variance
Α ^ , 4Α ^ , 3Α ^ , 2Α ^ , 10+1+2+3+4
+4+0.008+0.007+0.006+0.005+0.004+0.003+0.002+0.0010
+3+0.007+0.006+0.005+0.004+0.003+0.002+0.0010Α ^ , 0.001
+2+0.006+0.005+0.004+0.003+0.002+0.0010Α ^ , 0.001Α ^ , 0.002
+1+0.005+0.004+0.003+0.002+0.0010Α ^ , 0.001Α ^ , 0.002Α ^ , 0.003
0+0.004+0.003+0.002+0.0010Α ^ , 0.001Α ^ , 0.002Α ^ , 0.003Α ^ , 0.004
Α ^ , 1+0.003+0.002+0.0010Α ^ , 0.001Α ^ , 0.002Α ^ , 0.003Α ^ , 0.004Α ^ , 0.005
Α ^ , 2+0.002+0.0010Α ^ , 0.001Α ^ , 0.002Α ^ , 0.003Α ^ , 0.004Α ^ , 0.005Α ^ , 0.006
Α ^ , 3+0.0010Α ^ , 0.001Α ^ , 0.002Α ^ , 0.003Α ^ , 0.004Α ^ , 0.005Α ^ , 0.006Α ^ , 0.007
Α ^ , 40Α ^ , 0.001Α ^ , 0.002Α ^ , 0.003Α ^ , 0.004Α ^ , 0.005Α ^ , 0.006Α ^ , 0.007Α ^ , 0.008

PINION GEAR DEPTH VARIANCE

Scheme 304

Scheme 304: PINION DEPTH MEASUREMENT
Scheme 304: PINION DEPTH MEASUREMENT

Measurements are taken with pinion cups and pinion bearings installed in housing. Take measurements with a Pinion Gauge Set (special tool #6775, Kit, Master Pinion Depth), Gauge Block (special tool #8177, Gauge, Pinion Height) (6), Arbor Discs (special tool #8541A, Set, Arbor Disc) (8) and Dial Indicator (special tool #C-3339A, Set, Dial Indicator) (1).

Scheme 305

Scheme 305
Scheme 305

Scheme 306

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Scheme 306

Scheme 307

Scheme 307
Scheme 307
  1. Assemble Pinion Height Block (special tool #6739, Block, Height) (3), Gauge Block (special tool #8177, Gauge, Pinion Height) (6) and rear pinion bearing onto Screw (special tool #6741, Screw) (5).
  2. Insert assembled height gauge components (1, 2), rear bearing and screw into the housing through the pinion bearing cups.
  3. Install front pinion bearing and Cone-Nut (special tool #6740, Cone) onto the screw. Tighten cone-nut until Torque To Rotate the screw is 2.0 N.m (18 in. lbs.).
  4. Place Arbor Discs (special tool #8541A, Set, Arbor Disc) (1) on Arbor (special tool #D-115-3, Arbor) (3) in position in the housing side bearing cradles. Install differential bearing caps on arbor discs (1) and tighten cap bolts 61 N.m (45 ft. lbs.).
  5. Assemble Dial Indicator (special tool #C-3339A, Set, Dial Indicator) into Scooter Block (special tool #D-115-2A, Block, Scooter) and secure set screw.
  6. Place Scooter Block/Dial Indicator in position in the housing so dial probe and scooter block are flush against the surface of the pinion height block. Hold scooter block in place and zero the dial indicator. Tighten dial indicator face lock screw.
  7. Slide the dial indicator (3) probe across the gap between the pinion height block and the arbor bar (1) with the scooter block (2) against the pinion height block. Slide the dial probe to the crest of the arbor bar and record the highest reading.
  8. Select a shim/oil slinger equal to the dial indicator reading plus or minus the pinion depth variance number on the pinion gear. If the depth variance is -2, add 0.002 in. to the dial indicator reading. If the depth variance is +2, subtract 0.002 in. from the dial indicator reading.

DIFFERENTIAL BEARING PRELOAD

Before measuring differential bearing preload and gear backlash, pinion gear depth must be established and the pinion gear ready for installation. Pinion gear depth is essential to establishing gear backlash and tooth contact patterns.

Differential bearing preload and gear backlash is achieved with selective shims (2) (4) located between the differential bearing cups and differential housing. Shim thickness is determined using Dummy Bearings (special tool #8398, Set, Dummy Bearing) and Dummy Shims (special tool #8107, Shim, Dummy) in place of the differential side bearings and preload shims.

Scheme 308

Scheme 308: SHIM SELECTION
Scheme 308: SHIM SELECTION

Scheme 309

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Scheme 309

Scheme 310

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Scheme 310

Scheme 311

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Scheme 311

Scheme 312

Scheme 312
Scheme 312

Scheme 313

Scheme 313
Scheme 313

Scheme 314

Scheme 314
Scheme 314
  1. Remove side bearings from differential case.
  2. Install Dummy Bearings (special tool #8398, Set, Dummy Bearing) (4) on differential case.
  3. Install differential case in the housing.
  4. Install 3 mm (0.118 in.) thick Dummy Shims (special tool #8107, Shim, Dummy) (1) between dummy bearings (4) and differential housing.
  5. Install bearing caps in their correct positions and snug bearing cap bolts.
  6. With a dead-blow hammer (1) seat differential dummy bearing to pinion side (3) of the housing.
  7. With a dead-blow hammer (2) seat differential dummy bearing to ring gear side (3) of the housing.
  8. Thread Pin (special tool #C-3288-B, Set, Alignment Pins) (2) into cover bolt hole below ring gear.
  9. Attach Dial Indicator (special tool #C-3339A, Set, Dial Indicator) (3) to post and position dial indicator plunger on a flat surface on a ring gear bolt head.
  10. Push and hold differential case to pinion gear side (1) of the housing and zero dial indicator (3).
  11. Push and hold differential case to the ring gear side (3) and record dial indicator (1) reading.
  12. Add dial indicator reading to dummy shim thickness 6 mm (0.236 in), this is total shim thickness necessary to achieve zero differential end play.
  13. Add 0.2 mm (0.008 in) to the zero end play total. This is the total shims thickness needed to preload the new differential bearings. EXAMPLE: Differential Dial Indicator Reading + Dummy Shims 6 mm (0.236 in) + Preload Specification 0.2 mm (0.008 in) = Total Differential Shim
  14. Rotate dial indicator out of the way on pilot stud.
  15. Remove differential case, dummy bearings and dummy shims from the housing.
  16. Install pinion gear in the housing. Install the pinion flange (1) and establish pinion torque to rotating with an inch pound torque wrench (2).
  17. Install differential case and Dummy Bearings (special tool #8398, Set, Dummy Bearing) in the housing.
  18. Install a single (special tool #8107, Shim, Dummy) dummy shim in the ring gear side in the housing. Install bearing caps and tighten bolts snug.
  19. Position the dial indicator (3) plunger on a flat surface between the ring gear bolt heads.
  20. Push and hold differential case toward pinion gear (1) and zero dial indicator (3).
  21. Push and hold differential case to ring gear (3) side of the housing and record dial indicator (1) ring gear side reading. Add 3 mm (0.118 in.) one dummy shim thickness to ring gear side reading.
  22. Subtract backlash specification 0.05 mm (0.002 in.) from total ring gear side reading for ring gear backlash. This is the shim needed on the ring gear side of the differential. EXAMPLE : Ring Gear Side Dial Indicator Reading + One Dummy Shim 3 mm (0.118 in.) - Backlash Specification 0.05 mm (0.002 in.) = Ring Gear Side Shim
  23. Subtract ring gear side shim from total preload shim. The is the shim needed on the pinion gear side of the housing. EXAMPLE : Total Differential Shim - Ring Gear Side Shim = Pinion Gear Side Shim
  24. Rotate dial indicator out of the way on pilot stud.
  25. Remove differential case, dummy bearings and dummy shim from the housing.
  26. Install new side bearing cones and cups on differential case.
  27. Install Spreader (special tool #W-129-B, Spreader, Differential) and Adapter Plates (special tool #8142A, Adapters, Spreader) on the housing and spread open enough to receive differential case. CAUTION: Never spread over 0.50 mm (0.020 in). Failure to follow these instruction could result in distorting the housing.
  28. Place the side bearing shims in the differential housing against the housing shoulder.
  29. Install the differential case in the housing.
  30. Rotate the differential case several times to seat the side bearings.

Scheme 315

Scheme 315: GEAR BACKLASH
Scheme 315: GEAR BACKLASH

Scheme 316

Scheme 316
Scheme 316
  1. Position the dial indicator (1) plunger against a ring gear tooth (2).
  2. Push and hold ring gear upward while not allowing the pinion gear to rotate.
  3. Zero dial indicator face to pointer.
  4. Push and hold ring gear downward while not allowing the pinion gear to rotate. Dial indicator reading should be between 0.12 mm (0.005 in.) and 0.20 mm (0.008 in.). If backlash is not within specifications transfer the necessary amount of shim thickness from one side of the differential housing to the other.
  5. Verify differential case and ring gear runout by measuring ring to pinion gear backlash at eight locations around the ring gear. Readings should not vary more than 0.05 mm (0.002 in.). If readings vary more than specified, the ring gear or the differential case is defective.

After the proper backlash is achieved, perform the Gear Contact Pattern procedure.

Scheme 317

Scheme 317: GEAR CONTACT PATTERN
Scheme 317: GEAR CONTACT PATTERN
  1. Wipe clean each tooth of the ring gear.
  2. Apply gear marking compound to all of the ring gear teeth.
  3. Verify bearing cap bolts are torque to 61 N.m (45 ft. lbs.).
  4. Apply the brakes lightly to create a 14 N.m (10 ft. lbs.) pinion rotating torque.
  5. Rotate the pinion/pinion yoke 4 full revolutions in each directions.
  6. Read gear tooth contact pattern.

Gear contact pattern correct. Backlash and pinion depth is correct.

Scheme 318

Scheme 318
Scheme 318

Ring gear too far away from pinion gear coast side toe (1) drive side heel (2). Decrease backlash by moving the ring closer to the pinion gear.

Scheme 319

Scheme 319
Scheme 319

Ring gear too close to pinion gear drive side toe (1) coast side heel (2). Increase backlash, by moving the ring away from the pinion gear.

Scheme 320

Scheme 320
Scheme 320

Ring gear too far away from pinion gear drive side heel (1) coast side heel (2). Decrease backlash, by moving the ring closer to the pinion gear.

Scheme 321

Scheme 321
Scheme 321

Ring gear too close to pinion gear drive side toe (1) coast side toe (2). Increase backlash, by moving the ring away from the pinion gear.

Scheme 322

Scheme 322
Scheme 322

Pinion gear set too low. Increase pinion gear height, by increasing the pinion depth shim thickness.

Scheme 323

Scheme 323
Scheme 323

Pinion gear set too high. Decrease pinion depth, by decreasing the pinion depth shim thickness.

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