That all depends on how and where the vehicle is driven. I always recommend checking the manufactures recommendation on oil type, weight and mileage. Driving in the city with a passenger or two you are able to drive further than say someone who is working construction or pulling heavy trailers.

Using a heavier weight oil may void any warranties you have on your engine. The newer engines are now designed with tighter tolerances and the heavier weight oil may not lubricate the parts as thoroughly and could cause premature mechanical failure. Using the incorrect oil can decrease fuel mileage as well.

You should change the tire with your spare if at all possible. Using an aerosol tire fix will temporarily seal your flat tire but it does need to be properly patched. Newer vehicles with Tire Pressure Maintenance Systems (TPMS), the sealant will damage this sensor and depending on the manufacture can cost as much as $100 to have replaced.

Do not remove the nail or any object that is in your tire if you are not prepared to have a flat. It is possible that the way an object is in the tire that the tire rubber is sealed but once you remove it can leak. Drive to a tire repair facility and have them remove the object. Normally there is no charge for it but if it does leak after they remove it that they will be able to fix the flat.

Checking air pressure once a month at minimum will increase tire mileage and also increase your mpg. Tires are designed to run at certain air pressure to maintain the proper contact to the road. Over inflating or under-inflating tires will cause abnormal wear, increased road resistance and lower fuel mileage.

It should be changed but it depends on how old the fluid is. If your transmission has never had a service and you have over 100,000 miles on the oil, changing the worn/burnt oil may cause transmission failure. The additives and cleaning agents in transmission fluid do break down and wear out just like engine oil. Transmission fluid is designed to lubricate and clean you're transmission, old oil does not carry the worn particles or dirt to the filter and they become embedded in the seals and clutch plates. Putting new oil in an old transmission will clean the dirt and particles and can cause transmission to slip or loose the proper fluid pressure to the transmission causing failure as well. Refer to the manufacturers recommendations on changing the transmission fluid.

Just like engine oil and transmission fluid the differential oil also has specific requirements of lubricating and cooling of the gears and bearings in your differential. The differential is also vented so pressure is not built up in the differential but it can also allow contaminants in as well, water being the worst. If you have ever seen a differential cover where it looks like the paint is peeling from the metal indicates the oil has been over heated and the lubricating properties of the oil have been severely depleted. Changing the differential oil as recommended will increase differential life and costly repairs.

Freon is used in your A/C system that changes from liquid to a gas and back to a gas. The atoms are very small and over time will escape from the system. This is normal and yearly you should have your system checked so it is properly filled and working correctly.

There are a multitude of possibilities for this situation. You may just need a wheel alignment , which adjusts the front wheels to be in proper alignment when driving down the road. Worn parts in the steering and front suspension components could be worn out. Loose ball joints, worn idler arms or A frame bushings that are worn out can cause the tires to be misaligned going down the road. Prior to a front end alignment being done a thorough inspection should be done.

Most likely no. Brake dust can cause brake squeal. Depending on the type of brake material that was purchased for the vehicle, a cheaper pad/shoe will wear differently and the brake dust will cause the noise. Always chose the recommended manufacturer pad/shoe to help eliminate this problem.