Does your Ford Ranger make a clunking sound when you take off from a stop? You may think it’s from a bad u-joint, and some horrific problem in the rear axle. But in reality, it may simply be an issue of lubrication.
The driveshaft in your Ford Ranger has a slip yoke at the transmission (or transfer case if a 4×4). When you stop, the force causes the rear axle to rotate forward. This causes the driveshaft to be pushed forward. When you take off, the axle rotates up pulling back on the driveshaft. Without lubrication, the driveshaft sticks in the yoke. This causes a clunking sound.
The solution is to grease the shaft.
When doing so, you need to mark the driveshaft to make sure it goes back on in the position.
Chock the wheels or set the parking brake before removing the driveshaft. Otherwise, it’s going to start rolling away on you.
Remove the (4) 12-point 12mm bolts that hold the driveshaft on to the differential. If it doesn’t come off, you may need to strike it with a mallet or wooden block.
Once you get the driveshaft disconnected, slide it out of the yoke at the transmission/transfer case.
You can use a brake cleaner to clean out the yoke, but I WOULD NOT use it to clean the driveshaft.
The driveshaft has a blue coating on it, and you don’t want to ruin it.
Make sure you clean all of the old grease out of the grooves.
Once it’s clean, put a good coating of marine grease on it.
Ford actually offers a lubricant for slip yokes:
Genuine Ford Fluid XG-8 PTFE Lubricant – 3 oz.
Once you’re done, reinstall the driveshaft. The driveshaft may be keyed, which means the splines will only allow it to go back on one way. If you marked the driveshaft to align it back up, you shouldn’t have any problem. If the driveshaft isn’t keyed, it will go on any way you slide it together, so be sure you get it lined up in the same position it was in when you took it off.
Failing to put the driveshaft back on in the same position you took it off may cause a driveline vibration.