GM 19331451
Shock, Rear

The first step to replace a Shock Absorber on a 25 series vehicle requires vehicle support through axle lifting and use of a jack. Disconnect the electronic suspension control (ESC) electrical connector at the pigtail connector on the left side alone and at the top of the right side shock if installed and separate the esc sensor if available. Start by taking out the upper Shock Absorber nut followed by its bolt then detach the lower Shock Absorber nut followed by its bolt until the Shock Absorber is free. The new Shock Absorber goes in place first then uses the upper Shock Absorber nut and bolt for attachment before tightening both upper and lower Shock Absorber nuts to 95 nm (70 ft. Lbs.). The next steps involve reinstalling the lower Shock Absorber nut along with its bolt then starting by removing the rear axle support before reconnecting both the esc sensor and electrical connectors that were earler disconnected. The safety stands should be removed last while lowering the vehicle.

Vehicle elevation and support are necessary before jacking the lower Control Arm for Shock Absorber replacement. You can remove the electronic suspension control (ESC) link rod from its sensor when present after rotating the lock tabs counterclockwise first to unlock the connector. Pull up the connector to disconnect it properly. Starting from the tennon end apply a wrench to prevent loosening before removing the nut as you take off the upper insulator and maintain the plastic pilot ring in place. Separate the Shock Absorber mounting bolt at the lower Control Arm which applies to 15 series and 25/35 series units and extract the Shock Absorber. The installation process begins by feeding the Shock Absorber stem into the shock bracket on the frame while positioning it identical to the lower Control Arm mounting holes of both 15 and 25/35 series. Connect the Shock Absorber bolt to the lower Control Arm before installing its nut and tighten it to 80 n.m (59 lb ft). Secure the upper insulator onto the shock mounting bracket by placing it on the frame using the plastic pilot ring for placement and avoid tightening the nut on the tennon end. The esc link rod should be reconnected after which safety stands can be removed and the vehicle can be lowered. The tennon end requires torqueing with a wrench until it reaches 20 n.m (15 lb ft) before safe disposal of the Shock Absorber.

Ensure the upper insulator is installed above the shock mounting bracket on the frame, using the plastic pilot ring for alignment.

It may result in personal injury due to the contents being expelled with extreme force.

Lower the rear axle to facilitate the removal of the shock absorber, then take out the shock absorber.

Disconnect the RTD sensor.

Make an indentation in the middle of the tube with a centerpunch and drill a second hole at this centerpunch using the same 5 mm (3/16 inch) drill bit.

Align it with the lower control arm mounting holes and install the mounting bolts, tightening them to 25 Nm (18 ft. lbs.).