Checking The Drive Shaft
While searching to buy a used car the rear end of the machine should not be forgotten. To check that out there are just a few ways; the vehicle should be put into gear, is there a sound? Something like a loud clank? If yes then be sure that it is possible the drive shaft universal joint. Those joints are located on the ends of the drive shaft where the transmission connects to the rear differential.
If by any means, the universal joints can be ruled out then the rear gears come into question. They could be worn out but unfortunately, to check those the housing is required to be opened which, is not something a used car shopper looks forward to. You should have a certified technician at hand to identify that problem.
When on the road with the vehicle listens closely to the sounds the used car makes especially when you are on the highway and varying speed. In order to analyse the worn out rear gears you should look out for the following symptoms; a whining/ humming noise at a high speed. Vibrations can be felt through bad universal joints at high speed too in either of the two places, the body or the floor of the car. These components ought to be checked for leaks as they have seals and bearings too. There is a special fluid used to lubricate the gears in the rear end differential and that ought to be checked periodically like you will check any other vehicle fluid.