Ive got a 98 cherokee with around 112k and a slight knock. My question is if any of you guys here running synthetic oil in your motors. Im looking to hear some feedback on wether i should or not. And also if any of you guys using their tranny and gear oil too. TIA..

i run royal purple in my dakota, but not in the XJ. XJ motor runs pretty dirty, so i try to change the oil about every 3k miles. royal purple wouldn't be cost efficient. and also, i think the synthetic oils have low zinc level or something like that i've heard. and they say the 4.0 runs better on high zinc oil. but that's just the word of mouth that i've heard. you should research it a bit more before listening to me.

I've never used their motor oil but I use their gear oil and I have no complaints at all.

I used Royal Purple once, the first time I changed the oil in my 2001. Dark Purple goin in, clear as a bell on dipstick. Had to look twice to see if it was at the right level. Smoothed engine out and maby little more responsive. Quit drinkin beer the same day. So beware.

I switched from Mobil 1 to Royal purple. No appreciable difference I can see. It is a very good oil though. Seems to stay pretty clean.

Been running it for the last six months in crank and diffs. That and a Hastrings filter seems to be working just fine.

Synthetic oil is pretty much all about the same, just buy whatever. But I ALWAYS run synthetic oil, its way better for your engine, also buy 0-w30 if they have it, it decreases startup wear. With synthetic the thinner at room temperature the better, it all heats up to the same viscosity anyways.

Twak!
Think with ur dipstick Jimmy!

The only real differences between them is a couple of additives, otherwise its all the same stuff.

True but wit the same logic... The difference between drinking water and sewage is a few additives

I just like to go with an oil with a good reputation. Mobil 1 and Royal Purple both have excellent reputations.

mobil 1 full synthetic and mobil 1 extended performance contain the same about of zinc

They all have the same amount of zinc right up to the epa's standerds, the only oil that has more zinc is racing oil and boat oil .So there is no I use the best oil lol.

i use castrol or mobil 1 0-30 whichever is on sale.