Qusetion by: Ivan Balabanov Answer by: Michael HolleisI recently bought an ’00 Jeep Cherokee Sport 4.0 automatic with 239 000 km on the clock, no service history and the NP242 transfer box. What I’d like to know is: what oils / belts should I change and what grade of oil would you recommend? I’d like to do it myself.
THE EXPERT’S OPINION:
There isn’t a straightforward answer to this I’m afraid. The oil we get today has a very low zinc / phosphorous (ZDDP) content which is an additive used to protect extreme pressure areas of older engines, i.e. cam lobe / follower areas, etc. Today, many modern vehicles don’t suffer the same problem as they now use roller cams and other friction-reducing technologies.
For this reason I advise you use a 20W50 SL oil (any brand name will do) but be sure to add a ZDDP additive. This can be sourced from a company called Red Line Oils if you’re battling to find it.
With 239 000 km on the clock I’d change all the oils. For the rear diff use a 85W140 with a limited-slip additive available from most Chrysler dealerships. Use the same oil in the front diff, but no additive is needed. Dextron 3 ATF should be used in the automatic gearbox and transfer box. As for the belt, be sure to change the main serpentine belt and renew the idler pulleys too.
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