obads 31

Maybe this should be in the tow veh. section BUT here we go HYDRO/MIXGUY what would you reccomend for rear end and front end lube on a '98 5.9, and a '99 4.7 Jeep Grand Limited V8 Quadratrac ??? Also what type of auto-trans fluid ???? And what fluid in the transfer case??? Thanks CHEERS AW

minxguy

Sorry for the delay, I have been out of town on business, but here goes. Regardless of the viscosity, I would use a full Synthetic product in the differentials, just make sure the product is ok with limited slip and GL-5 rated. I personally use Spectro Platinum Full Syn Gear Oil 75w140 GL-5 in both my front a rear diffs and my outdrive. I use Motorcraft tranny fuid and change it regularly. I also use Spectros full syn gear oil in my transfer case, same viscosity. My truck is a F-250 with 180,00 miles. Jeep may have different specs for transfer case fluid. Check with your owners manual. Hope this helps. Ken

obads 31

Ken,
Thanks for the info. I've had great luck and longevity with M1 15-50 in cars and boats . Started thinking about what to put in the dif's of my Jeeps after reading how different lubes work ( OR DON'T ) in drives. I've had JEEP rebuild my front dif 40,000 mi. ago and it's starting to whine again. Thought if I used something with additives I might keep the whine down and make it live a little longer.

CHEERS AW

minxguy

AW, unless you are really hurting it, the diff should last more than 40,000 miles,providing it was rebuilt properly. Is it a limitded slip? If so make sure the oil that you use has "factory fill" treat rate of the LS additive. If it doesen't you either have to buy the little bottle at the parts store or change more often than 40,000.miles. Ken

cloudmaster_321

So with some of the book here that i have read, it sounds like 20w-50 mobile should be used in place of the 15w-50? I currently have the 15w-50 mobile with the wix racing filter, i was thinking about putting the mobil filter on, but now unsure about what oil to run. I have a slightly modified 502 efi. Trying to get this thing winterized, we are forcasting some snow flakes her by thursday already............crazy. But need to change the oil this weekend. What should i use.

minxguy

Cloudmaster, 20w50 will work just fine. The only difference between the 15w50 and the 20w50 (I'm talking viscosity here not aditive content) is that the 15w50 has a lower pour point. The 20w50's pour point is -10F, maybe even lower. The point being, when the pour point of a 20w50 oil becomes an issue, you couldn't make a big enough hole in the lake to splash your boat. In the spring at 40-50 degrees you will be more than fine.Ken

sleeper_dave

Okay, i'm only on page 10, so forgive me if these questions have been "asked and answered":

WTF is ZDDP? It sounds like the holy grail... but it's not listed on the oil analysis reports posted and it's not in the bobistheoilguy glossary. What does it stand for? How do you know if there's a lot of it (other than reading here)?

Also,

How cold is too cold for engine oil? I think my oil temp gauge saw 160 once this year. Every other time out, it would barely top 140, if that. Now that the water is cooling back down, the needle hardly budges, doesn't even touch 140. Do I need an oil thermostat?

cloudmaster_321

Well, don't know what to run then. I think i have seen the 20W-50 at fleet farm just the same as 15W-50. Which should i use?

minxguy

Run the 20w50. Ken

Rebel_Heart

If I only have 12 hours on new 540s, would you use the same oil that is currently in the engines for an oil change prior to putting away for the winter? I am now using Valvoline 40w. Or, should I change to Mobil 1? I didn't know if I had enough hours on the engines to switch to a synthetic. Would you ever change to a synthetic, if so, what would you use? I am using the Wix racing filters. Thank you.