Completing basic chores such as changing the oil and transmission fluid will keep your 4x4 running stronger longer. Here we use Pennzoil Platinum full-synthetic motor oil to fill the high-mileage 4.0L I-6 in our Jeep Cherokee.
Chores like raking leaves and cleaning the garage are easy to ignore weekend after weekend, but when it comes to maintaining your 4x4 a reluctance to get the job done can have catastrophic effects. Jobs such as changing the engine oil and transmission fluid are ever-important steps in keeping your 4x4 in excellent running condition and are often overlooked or delegated to the quickie-lube station that may use inferior products. Use of inferior products can extend beyond the quickie-lube station as well. It's pretty easy to be tempted by whatever oil is on sale at the auto parts store, but be aware you typically get what you pay for and your engine will reflect the purchase.
With nearly 160,000 miles on the 4.0L I-6 in our Cherokee, we wanted motor oil able to withstand fairly severe conditions. We even considered switching to a high-mileage motor oil, which is usually offered in higher viscosity and includes special additives to slow oil burn-off. Instead, we decided to reach all the way to the top shelf and fill the engine with the new, full-synthetic Pennzoil Platinum, which is said to offer superior antiwear protection and consistent engine performance.
Pennzoil Platinum is a full-synthetic motor oil available in 5W-20, 5W-30, 10W-30, 5W-40 Euro, and 5W-30 Euro. We chose the higher-viscosity 10W-30 to address our high-mileage needs, but newer, lower-mileage vehicles can get away with the 5W-30. 5W-30 is also advised in colder climes since it will flow better in colder temperatures. If you're unsure what oil viscosity to use in your vehicle, you should first check with the vehicle's manufacturer to see what it recommends. In any case, 10W-30 is pretty darn close to a one-size-fits-all oil, so it should suffice in most engines.
We'll use Pennzoil Multi-Vehicle ATF and a new Fram transmission filter supplied by Summit Racing to service the AW4 automatic transmission. | 
The full-synthetic Pennzoil Platinum will be used along with a Fram Tough Guard oil filter. A new pan gasket was supplied by Summit Racing. | 
The Fram Tough Guard oil filter features the company's SureGRIP nonslip end for easy handling and installation, and it uses a combination of synthetic glass and cellulose media to achieve a 99-percent multipass filtration efficiency. Also, a silicone anti-drainback valve is in place to retain oil while the engine isn't running so it will have an ample supply at start-up. |
We've already experienced more than our fair share of rusted bolts while working on our Cherokee, so we thought ahead and picked up some Pennzoil Z-4 multipurpose lubricant and Z-Q quick penetrant. | 
Before removing the trans pan, we cleaned up the bolts using the Z-Q quick penetrant. After letting the Z-Q settle in, a rag was used to remove the built-up grease and dirt. | 
Once the fluid was drained, the transmission pan was removed as was the old filter, which was closely inspected for metal shavings and other debris. |