Hey guys, I recently purchased a Jeep a few months back and I'm about to do an oil change. The previous owner has been using 10w-30 oil. The differential oil hasn't been changed to my knowledge. I asked my gf to pick up oil, she got 5w-30, and RP 75w-90 gear oil. I was wondering if there was anything wrong with going from 10w-30 -> 5w-30. Should I go back and return the oil and pick up 10w-30 or is it insignificant? The engine has about 54k miles on it. The car has 146k

Thanks

 

I ran 5w30 oil in mine for a few intervals. nothing wrong with it unless you're a gauge watcher. it will show considerably lower pressure at full operating temp vs 10w30. I got my best gas mileage with 5w30. I switched from conventional 5w30 to synthetic 5w40 (rotella t6) because I wanted extended oil change intervals, and the t6 line of rotella oils is next none. since stopping my oil leaks I now go 7-8k miles on the oil using a wix 51515 filter. thankfully my last OCI required no added oil, and the dipstick showed it just a hair under full - 7500 miles.


I use mobil 1 75-90 in my difs. I don't go offroad, so contaminating the fluid forcing a fluid change is not of concern. if you will be changing fluids often from offroading, I'd find the cheapest 90wt oil you can. otherwise, what you have will be fine.

 

No problem: the 5W30 and 10W30 are both the same viscosity at operating temp, and the 5W30 flows better when cold.

 

Should I open the differential and clean it?

 

Unless it's leaking, no need to remove the cover. Just drain n' fill.

 

Also I live in new york, Its going to get very hot this summer, is it bad to run 5w-30 in the summer heat?

 

Ummm....you have to remove the cover to drain. LOL

 

If there's no drain plug, then, yeah. Since he asked, I assumed he had the option to do either.

 

^^ Good stuff here. Synthetic gear oil provides a lot of advantages, especially when cold. Gear oil takes a very long time to heat up compared to other fluids in your Jeep. However it's a little cost prohibitive if you sink your axles.

Yes. In all of the factory Jeep axles there is no drain plug, so if you want to get it all out (not via a suction pump) you have to take the cover off. If you don't know the history it's good to take a look around inside and blast any crud off.

Don't use chlorinated brake cleaner, and don't take any deep breaths lol.

Nope. About 20 years ago it made a difference. Oil isn't what it used to be.

 

Thanks everyone! Salad,I've got 3M hi-power brake parts cleaner. Anything else you can recommend? It doesn't seem to have chlorine according to the label. Also when I open the differential, cleaning the old gaskets off, besides a scraper, what else should I use? I dont have any air grinders etc. Can I use sandpaper for the hard to scrape areas?

Thanks

 

Not much that's hard to scrape really, I'd avoid using a scraper as the differential is cast iron and it's good not to score it. Every time I've done my diffs I used a $20 electric angle grinder and $5 crimped wire cup brush. Gets RTV off and any nearby rust.

 

Will a dremel tool work?

 

Yes... but very slowly and will lack power to blast any rust off. A 1" wire brush would be the minimum.

If you live in New York State you will find many many many many uses for an angle grinder and wire brush. Can't go wrong lol

 

Use paper gaskets and permatex high tack. Trust me.

 

Where do I get these paper gaskets? Are they pre-cut?