You have to remove the driveshaft, and with an air impact remove the large nut, there's the seal.
There is one on each end of the crankshaft. The front main seal is at the pulley and, while the rear main is at the transmission end.
The rear chankshaft seal is on the back end of the engine above the pan and at the rear of the crankshaft.
The easiest way to do it- both get at the front end for the timing kit and the rear seal is unfortunately to remove grill and radiator- unbolt tranny and engine and kind of slide it forward
Remove the tire and wheel from your 2003 GMC 2500 Sierra. Remove the end of the axle. Using a seal puller remove the axle seal. Reverse the process to install your new rear axle seal.
At the yoke at the rear end (where drive shaft enters rear end)
Remove the you joint and driveshaft. Remove the rear end seal plate. Remove the seal and bearing. Reverse the process to install the new seal.
Find out where. Usually transmission fluid leaks from either the front or rear seal. The front seal (between the engine and transmission) requires that the engine or transmission be removed from the vehicle for replacement. The REAR seal (assuming Rear wheel drive) can be replaced by removing the driveshaft from the transmission tail. Front wheel drive vehicles typically have a seal on each of the "half shafts", and each manufacturer handles that differently. Sometimes you need to take the front end apart, sometimes it's just a few bolts. Sometimes it's an entire transmission rebuild.
if the queue contains one element then front end is equal to the rear end.
What type of rear end do you have?
new shocks in front and old in rear??
The front hood raises from the rear or windshield end, the rear hood raises from the rear or bumper end
Any brand of WD40 oil will work.