Valeoscope Commercial Vehicles Clutch 2020

Diagnosis Hard gear shifting

6. Partially burst facing

7. Dirty splines/oxidation on splines

8. Worn and seized splines

9. Damaged pilot bearing

Parts inspection The facings are broken along the lines joining rivets, pieces of facing is snatched out and then are stacked. Vehicle behaviour Hard gear shifting  clutch does not release. Reasons ●● Partial burst is due to high rotation speed of the clutch disc (rotation speed higher than burst speed). ●● Mis-shifting or mistake of range shift position.

Parts inspection ●● It is difficult (sticking) or impossible (seizing) to rotate the pilot bearing. ●● The pilot bearing is destroyed (ball and ball cage destroyed). Vehicle behavior ●● It is impossible or difficult to shift gears. ●● This issue is wrongly associated to several reasons related to cover assembly or clutch disc. Reasons ●● The pilot bearing is dried due to overheating of flywheel. ●● Insufficient quantity of grease inside the pilot bearing (grease has been ejected due to air pressure during introduction of gearbox input shaft). ●● Deterioration of grease (aging, drying, facing dust…). ●● Deterioration of ball cage during gearbox assembly (shocks of gearbox input shaft). ●● Wrong positioning of the pilot bearing.

Dirty splines / oxidation on splines

Worn and seized splines

Parts inspection ●● The clutch disc splines are clogged (grease and dust…). ●● Oxidation marks on both clutch hub splines and input shaft splines; seizing is due to the lack of greasing. ●● The input shaft splines are damaged (shocks, wearing or caulking). Vehicle behavior Hard shifting for each gear because of insufficient displacement of the clutch disc on the input shaft. The facing remains in contact with the flywheel. Reasons ●● Grease was not applied on splines during assembly operation (or insufficient quantity of grease was used). ●● No suitable grease has been used. ●● Damaged splines. Attention Ɂ Ɂ Valeo has designed hub nickel plated clutch discs that do not require greasing. In such cases, specific instructions are provided with the disc. Advice   Use appropriate grease recommended by the manufacturer if necessary. (Refer to Valeoscope maintenance chapter)

Parts inspection ●● Splines are worn or caulked ●● Shock marks on side of splines Vehicle behavior Shifting is difficult for each gear, due to wrong disc sliding on the input shaft of the gearbox. Reasons ●● Wrong handling during assembly (shocks during ●● Wrong disc part number has been used (Splines dimensions do not match with the gearbox's input shaft). ●● Large engine vibrations. Advice   Check if the disc used fit the gearbox (check the part number).  Center the disc with the appropriate tools and carefully mount the gearbox.  Check the engine's conditions and adjustments. gearbox mounting operation). ●● Misalignment engine/gearbox.

Partially burst facing

Attention Ɂ Ɂ Gearboxes require careful handling. Such issues may occur while mis-shifting or when using “repaired” products.

Pilot bearing damaged

Attention Ɂ Ɂ Check the positioning and the holding of the pilot bearing (wear of bearing housing or wear of gearbox input shaft tip). Carefully assemble the gearbox.

Advice   Replace the pilot bearing each time you replace the clutch.

30

31