Upgrade or standard parts

My typical reply would be it depends on how it was taken care of, however, I recently retired my 1988 Dodge Grand Caravan because it was so rusty, the carpet was the only thing holding the front and rear together. The engine developed an elusive knock that I mistakenly assumed meant it was near the end, so I stopped changing the oil. Over time it became apparent the noise was not the end, but by then it had become an experiment to show my students what some engines are capable of. It had reached 420,000 miles, was still going strong, and it had been fourteen years and over 140,000 without an oil change. That is not neglect; that is abuse, and obviously I am not recommending anyone else do that. To add to the misery, I used it to regularly drag around a tandem-axle enclosed trailer that is bigger and heavier than that van.

The biggest advantage I had was that van had just one computer, for the engine. Your vehicle has numerous computers that will result in multiple expensive repairs, but that can be said of any newer vehicle. If you are trying to figure out if it is better to keep your truck or trade it for fear of developing a mileage-related failure, you have to look at how you would acquire your next vehicle. If you trade at a dealership, consider that a large majority of people trade when their current vehicle develops a major problem. The dealers know that and the trade-in value takes that into account. For example, suppose they offer you $2,000.00 toward the cost of a new car when you tell them your trade-in needs a major engine repair. You would typically be offered only a few hundred dollars more if there was no engine problem. You are better off keeping and driving the old vehicle until a major problem develops, if it ever does.

Back in the 1970's, 150,000 miles was informally considered to be the life expectancy of a car with one notable exception that lasted only 75,000 miles. Today, other than scheduled timing belts and timing chains, 300,000 miles is common. Also, consider that we drive a real lot more today so those miles add up real fast while everything else is still relatively new. Some people drive two hours one way to work, then two hours back home. If those are highway-speed miles, those cause extremely little wear to the engine. Most engine wear takes place in the first couple of minutes when it is warming up. When it is still cold, some parts, pistons in particular, do not fit well. The oil is still cold so it does not flow well to some critical points. Blowby gases form sludge in the oil. Much of that blowby vaporizes and is drawn out when the engine is hot. Excessive short-trip driving does not get the engine hot enough long enough, so that sludge further reduces the oil's ability to clean and lubricate. That leads to lots of wear on low-mileage engines.

Fuel mileage and emissions have been handled by the engine computer before the exhaust gas leaves the engine. What happens to that exhaust after that does not affect fuel mileage. Catalytic converters are very free-flowing already. They do not offer any restriction to flow. What does happen quite often is aftermarket replacement catalytic converters do not work exactly the same as the originals, and that is detected as an efficiency problem. A related diagnostic fault code will be set, and since that defect could adversely affect emissions, it will turn on the check engine light. A lot of 1996 and newer vehicles must use the original manufacturer's catalytic converters for the emissions system to work properly.

Two things happen when the check engine light is on. The first is if a second, different problem is detected, you will never know it because the warning light is already on. That second problem could be very minor, but turn into an expensive repair when it is ignored.

The second problem is the engine computer is constantly watching up to 2,000 things, and it intermittently runs self tests on various systems. Some of those tests are analyzed by comparing two or more things to each other. As an example, when the engine has been off for more than six hours, the computer knows the coolant temperature sensor and the intake air temperature sensor had better be reading the same temperature. It also knows if the throttle position sensor says the throttle is closed, the engine speed had better be at idle speed or close to it.

When a defect has been detected, in this case, the catalytic converter efficiency problem, any self-tests that need to see the results as changes in oxygen sensor readings will be suspended because the computer knows it cannot rely on the readings it uses for comparisons. With some tests suspended, a new problem could develop, but it will not be detected. If that new problem causes an engine running problem, there may be no diagnostic fault code related to it, and without that, you will have no way of knowing which circuit or system needs to be diagnosed.

Some systems on some engine computers go to a default mode when the check engine light is on. In that mode, the computer may stop operating some systems that provide better fuel mileage to instead, insure the engine runs smoothly with no surging or hesitations. As an example of this, newer Dodge V-8 truck engines cut off fuel to four cylinders at highway speed when they are not needed, to save fuel. Those trucks can achieve twenty eight miles per gallon in that mode. If a totally unrelated problem is detected and the check engine light turns on, the computer will not go into that fuel-saving mode. This is where fuel will be wasted unnecessarily.

Automotive marketing is extremely competitive. If a manufacturer could advertise one more cubic foot of leg room, one more horsepower, one more cup holder, or one more mile per gallon, you can be sure they would do it. If there was anything they could do to the exhaust system to increase power or fuel mileage without sacrificing emissions, you can be sure they would have done it. Do not expect to find anything you can do that they did not already try, regardless of what the advertising propaganda says.

Magnaflow does a lot of research on there items. So I do believe they are good for emissions. Make sure that you talk to the Magnaflow company and make sure that there pats that you got are emission complainant.

That depends on how much clearance you have in the wheel well. The 275 is the size and the 45r is the with of the tire. The tire you want to put on are a little wider than you have on there now.

I would say a rebuilt transmission would be better, they install new parts and make sure everything is clean and working right. On a rebuilt transmission you do not know if it had any problems prior to you getting it. Some work great and some have problems. If you go with a rebuilt one make sure there is some kind of warranty in case it does not work right.

Just like I said, you do not know if it has a shifting problem, or not going into gear, or a automatic transmission fluid circulation problem. You would be getting something that has been used. Check the seller for a warranty of some kind. Most places will sell you one with a ten to thirty day guarantee.

I had my 1997 Silverado transmission rebuilt two years ago and one year 12,000 miles is the standard warranty now days.
Danny-

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Cheers, Ken