Rupunzell
Bernice Loui
Inspect the crown gear on the diff housing for excessive wear, broken teeth and any other visual defects. Inspect the spider gears and their spherical bearing surface. The spider gears can be rotated within he diff carrier to inspect them. Also check for excessive spider gear backlash.
On a stock exxe, problems in this area is rare. On exxe's run very hard or raced with significantly more power than stock, very carefully inspect the diff carrier for cracks or other hidden problems. This means taking the spider gears out of the diff carrier, removing the crown gear and getting the diff carrier magna fluxed. Diff carriers have been known to explode under really hard race conditions.
The rough should be ground smooth then properly shot peened to remove potential hidden stress risers that grow into cracks causing a diff carrier failure under high stress conditions.
If all is well, torque/ check the M10x1.25 grade R12 (12.9) x 25mm long cap screws to Fiat spec of 65 ft/lb in a cross pattern using a 13mm hex socket and torque wench to assure uniform clamp loading of the crown gear onto the diff carrier.
If the diff, spider gears, crown gear and all are checked and pass inspection. Remove and replace the tapered roller diff carrier bearings using the correct puller as they are often worn. In severe cases, the outer bearing races will have areas of missing metal.
Tapered roller bearings removed from the diff, press on the new bearings using the correct arbor on a press that applies pressure only on the center of the bearing race. If installation pressure (few thousand pounds aka tons of force folks) is applied to the rollers and retainer cage, bearing damage will result ending in a failed bearing in short time. Note the aluminum plate on the bottom of the diff carrier used to protect the diff carrier bearing surface.
An old bearing inner race that has been modified can be used to fully seat the tapered roller bearing inner.
Repeat this procedure for the opposite end of the diff.
Removing the outer bearing race in the case is always fun. After dealing with this struggle for years, this puller head was designed and built specifically to remove that race. There are two slots under the race, the puller head fits two blades into those slots and under that bearing race applying pressure to remove it.
The USAG adjustable puller leg frame is no longer available. It is this special puller frame, puller head on a rod end that allows easy removal of this tapered bearing race.
Slide hammer with attachment used to remove the shifter seal. The shifter seal is removed with one or two whacks of the slide hammer.
This is the shifter seal boss with the seal removed. On the left is a M8 stud. If this stud is removed, there will be a oil leak as the threaded hole goes into case in an area filled with oil. This is why Fiat installed a M8 stud here. If it is removed, reinstall the stud using Loctite or at the very least thread sealant.
No silicon gasket goo is allowed in this shop. Hylomar is the only stuff allowed. Apply a thin coat on the new shifter shaft seal and install it.
New shift shaft seal installed.
Case in press, with the new tapered bearing outer race and aluminum race press arbor. The arbor is made of aluminum to prevent damage to the outer bearing race and has three steps cut into it to center the race and fully seat the race into the bore. Lube the outer bearing race and housing bore with oil prior to pressing the race into the bore. Failure to do this promotes galling of the aluminum as the bearing race is pressed into the bore.
New tapered bearing outer race being passed in to the bore.
New outer race installed and fully seated into it's bore. Next, install the oil seal while the whole thing is in the press. Coat the new oil seal with Hylomar prior to installation.
Oil seal is installed using an arbor that fits inside the bearing outer race and larger than the oil seal.
Tapered roller bearing outer race installed, new oil seal installed.
The lower transaxle case is now ready for re-assembly.
Next up, gear sets and shift forks, shift rods and shift translator assembly.
Bernice
On a stock exxe, problems in this area is rare. On exxe's run very hard or raced with significantly more power than stock, very carefully inspect the diff carrier for cracks or other hidden problems. This means taking the spider gears out of the diff carrier, removing the crown gear and getting the diff carrier magna fluxed. Diff carriers have been known to explode under really hard race conditions.
The rough should be ground smooth then properly shot peened to remove potential hidden stress risers that grow into cracks causing a diff carrier failure under high stress conditions.
If all is well, torque/ check the M10x1.25 grade R12 (12.9) x 25mm long cap screws to Fiat spec of 65 ft/lb in a cross pattern using a 13mm hex socket and torque wench to assure uniform clamp loading of the crown gear onto the diff carrier.
If the diff, spider gears, crown gear and all are checked and pass inspection. Remove and replace the tapered roller diff carrier bearings using the correct puller as they are often worn. In severe cases, the outer bearing races will have areas of missing metal.
Tapered roller bearings removed from the diff, press on the new bearings using the correct arbor on a press that applies pressure only on the center of the bearing race. If installation pressure (few thousand pounds aka tons of force folks) is applied to the rollers and retainer cage, bearing damage will result ending in a failed bearing in short time. Note the aluminum plate on the bottom of the diff carrier used to protect the diff carrier bearing surface.
An old bearing inner race that has been modified can be used to fully seat the tapered roller bearing inner.
Repeat this procedure for the opposite end of the diff.
Removing the outer bearing race in the case is always fun. After dealing with this struggle for years, this puller head was designed and built specifically to remove that race. There are two slots under the race, the puller head fits two blades into those slots and under that bearing race applying pressure to remove it.
The USAG adjustable puller leg frame is no longer available. It is this special puller frame, puller head on a rod end that allows easy removal of this tapered bearing race.
Slide hammer with attachment used to remove the shifter seal. The shifter seal is removed with one or two whacks of the slide hammer.
This is the shifter seal boss with the seal removed. On the left is a M8 stud. If this stud is removed, there will be a oil leak as the threaded hole goes into case in an area filled with oil. This is why Fiat installed a M8 stud here. If it is removed, reinstall the stud using Loctite or at the very least thread sealant.
No silicon gasket goo is allowed in this shop. Hylomar is the only stuff allowed. Apply a thin coat on the new shifter shaft seal and install it.
New shift shaft seal installed.
Case in press, with the new tapered bearing outer race and aluminum race press arbor. The arbor is made of aluminum to prevent damage to the outer bearing race and has three steps cut into it to center the race and fully seat the race into the bore. Lube the outer bearing race and housing bore with oil prior to pressing the race into the bore. Failure to do this promotes galling of the aluminum as the bearing race is pressed into the bore.
New tapered bearing outer race being passed in to the bore.
New outer race installed and fully seated into it's bore. Next, install the oil seal while the whole thing is in the press. Coat the new oil seal with Hylomar prior to installation.
Oil seal is installed using an arbor that fits inside the bearing outer race and larger than the oil seal.
Tapered roller bearing outer race installed, new oil seal installed.
The lower transaxle case is now ready for re-assembly.
Next up, gear sets and shift forks, shift rods and shift translator assembly.
Bernice
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