Well it sounds to me like they don't know what they are doing. Since you already paid for the work, and they are repairing it for free, I doubt you will get your money beck. So your only option is to have them reset the whole diff with new bearings and to follow the proper procedure. Do you have your own factory service manual? If you do, bring it to them so they can do the setup correctly. I will cut and paste the proper procedure for you, print this out and bring it down to them when you bring it back. Once you get it back, check the fluid level yourself to make sure they aren't being really stupid. Make sure they follow the instructions carefully, it is easy to screw up this procedure if they aren't careful.
Bryan
Pinion gear set-up:
INSTALLATION
Apply Mopar® Door Ease, or equivalent, stick lubricant to outside surface of bearing cup.
Install the pinion rear bearing cup Pinion Rear Bearing Cup Installation with Installer C-4308 and Driver Handle C - 4171.
Ensure cup is correctly seated.
Apply Mopar® Door Ease, or equivalent, stick lubricant to outside surface of bearing cup.
Install the pinion front bearing cup Pinion Front Bearing Cup Installation with Installer D - 130 and Handle C - 4171.
Install pinion front bearing, and oil slinger, if equipped.
Apply a light coating of gear lubricant on the lip of pinion seal. Install seal with Installer C-4076 - B and Handle C-4735-1 Pinion Seal Installation
NOTE: Pinion depth shims are placed between the rear pinion bearing cone and pinion gear to achieve proper ring and pinion gear mesh. If the factory installed ring and pinion gears are reused, the pinion depth shim should not require replacement. If required, refer to Pinion Gear Depth to select the proper thickness shim before installing rear pinion bearing.
Place the proper thickness depth shim on the pinion gear.
Install the rear bearing and slinger, if equipped, on the pinion gear Shaft Rear Bearing Installation with Installer 6448.
Install a new collapsible preload spacer on pinion shaft and install pinion gear in housing Collapsible Preload Spacer
Install pinion gear in housing.
Install yoke with Installer C-3718 and Yoke Holder 6719.
Install the yoke washer and a new nut on the pinion gear and tighten the pinion nut until there is zero bearing end-play. It will not be possible at this point to achieve zero bearing end-play if a new collapsible spacer was installed.
Tighten the nut to 285 N·m (210 ft. lbs.)
CAUTION: Never loosen pinion gear nut to decrease pinion gear bearing rotating torque and never exceed specified preload torque. If preload torque or rotating torque is exceeded a new collapsible spacer must be installed. The torque sequence will then have to be repeated.
Using Yoke Holder 6719, crush collapsible spacer until bearing end play is taken up.
Slowly tighten the nut in 6.8 N·m (5 ft. lbs.) increments until the desired rotating torque is achieved. Measure the rotating torque frequently to avoid over crushing the collapsible spacer Check Pinion Gear Rotating Torque
Check bearing rotating torque with an inch pound torque wrench Check Pinion Gear Rotating Torque The torque necessary to rotate the pinion gear should be:
Original Bearings - 1 to 3 N·m (10 to 20 in. lbs.)
New Bearings - 2 to 5 N·m (15 to 35 in. lbs.)
Install propeller shaft.
Install differential in housing.
Carrier bearing installtion and preload procedure:
DIFFERENTIAL BEARING PRELOAD AND GEAR BACKLASH
The following must be considered when adjusting bearing preload and gear backlash:
The maximum ring gear backlash variation is 0.003 inch (0.076 mm)
Mark the gears so the same teeth are meshed during all backlash measurements.
Maintain the torque while adjusting the bearing preload and ring gear backlash.
Excessive adjuster torque will introduce a high bearing load and cause premature bearing failure. Insufficient adjuster torque can result in excessive differential case free-play and ring gear noise.
Insufficient adjuster torque will not support the ring gear correctly and can cause excessive differential case free-play and ring gear noise.
NOTE: The differential bearing cups will not always immediately follow the threaded adjusters as they are moved during adjustment. To ensure accurate bearing cup responses to the adjustments:
Maintain the gear teeth engaged (meshed) as marked.
The bearings must be seated by rapidly rotating the pinion gear a half turn back and forth.
Do this five to ten times each time the threaded adjusters are adjusted.
Use Wrench C-4164 to adjust each threaded adjuster inward until the differential bearing free-play is eliminated Threaded Adjuster Tool Allow some ring gear backlash (approximately 0.01 inch/0.25 mm) between the ring and pinion gear. Seat the bearing cups with the procedure described above.
Install dial indicator and position the plunger against the drive side of a ring gear tooth Ring Gear Backlash Measurement Measure the backlash at 4 positions (90 degrees apart) around the ring gear. Locate and mark the area of minimum backlash.
Rotate the ring gear to the position of the least backlash. Mark the gear so that all future backlash measurements will be taken with the same gear teeth meshed.
Loosen the right-side, tighten the left-side threaded adjuster. Obtain backlash of 0.003 to 0.004 inch (0.076 to 0.102 mm) with each adjuster tightened to 14 N·m (10 ft. lbs.) Seat the bearing cups with the procedure described above.
Tighten the differential bearing cap bolts 95 N·m (70 ft. lbs.)
Tighten the right-side threaded adjuster to 102 N·m (75 ft. lbs.) Seat the bearing cups with the procedure described above. Continue to tighten the right-side adjuster and seat bearing cups until the torque remains constant at 102 N·m (75 ft. lbs.)
Measure the ring gear backlash. The range of backlash is 0.006 to 0.008 inch (0.15 to 0.203 mm)
Continue increasing the torque at the right-side threaded adjuster until the specified backlash is obtained
NOTE: The left-side threaded adjuster torque should have approximately 102 N·m (75 ft. lbs.) If the torque is considerably less, the complete adjustment procedure must be repeated.
Tighten the left-side threaded adjuster until 102 N·m (75 ft. lbs.) torque is indicated. Seat the bearing rollers with the procedure described above. Do this until the torque remains constant.
Install the threaded adjuster locks and tighten the lock screws to 10 N·m (90 in. lbs.)
After the proper backlash is achieved, perform the Gear Contact Analysis procedure.
