slowjunk

going to be changing the axles fluid this week. i done some research and found mix opinions on which axle gear oil everybody used. some said to use 75w 90 other said 80w 90. also do i really need gasket for the covers or rtv gasket maker is good? my xj is a 92 laredo and it does have a tow hitch receiver. it's a daily drive not planning to tow anything or off road anytime soon.

DFlintstone

Here I think 85-90 is what I get. And yea, I just started using only silicone after wrenching all my life! I'd see that and thought it was "cheezy". Silicone alone works. If it's hot and dry the black might set pretty fast. Blue is used allot.

A quality gasket with silicone only on the cover side might give you the option to pull it. Others here can fill in....

F1Addict

Manufacturer recommends 75-90 and so do I. RTV is fine if you don't mind aesthetics or waiting a few hours for it to cure before refilling. Or you can use Lube Locker gaskets... no waiting and reusable but a little more expensive than RTV.

xj wheeler

It was recommended to me to use 75-140 in the rear by an extremely knowledgeable buddy. And 75-90 is the usual up front.

An 1/8" bead of ultra black rtv does the trick. And is hardly visible, if its a big worry just wipe off the excess.

Don't forget to clean the mating surfaces of the diff and cover. And inspect the gears while you're in there.

BMAC6642

I run 50wt gear oil in mine. If you have posi's don't forget the additive for them.

94XjSport94

He recommended that for if you tow or the rear is under heavy loads. Just use house brand 80w-90 and change it after every wheeling trip you go on and good regular intervals.

caged

every wheeling trip, really? you do that?

i do mine twice a year, and it's still clean when i do it.

75-90, 80-90, 85-90... not much difference. just be sure to use the additive for LSD, if equipped. i can't even remember what i bought last.

ultra black rtv on clean surfaces, apply to the cover and wait a few minutes, then carefully set cover on axle and finger tighten the bolts in a star pattern.
wait a few mins, then tighten a bit more, in star pattern.
wait some more and tighten to 20lbs.
wait a bit, then fill till it starts to come out of the fill hole. wipe up access, apply some rtv around the plug and tighten that till it's snug, about 25lbs.

sycoglitch

Wheeling.trips if you submerged the axles so as to not have a water oil mix.

94XjSport94

Yep. I always end up in nastier stuff than I want to. I go wheeling just about once a month. That's my general rule, but I don't always do it lol.

belvedere

Gaskets or RTV are fine. If you want the best, though, I recommend the Right Stuff.

slowjunk

guess i'll go with 75-90 since it's the most used in the house. so only put rtv on the cover side not both sides of the gasket correct? as far as additive fluid what happen if i don't add to the oil fluid? it's a dana turdy 35 btw.

DFlintstone

You can go with just RTV and no gasket. If you do use a gasket, since the diff side is guaranteed perfectly flat, you might use sealant on the cover side only, then have the option to remove and replace it. (that applies to other things as well).

Like caged suggested, I just used RTV, no gasket last time. It seals with no hassle, and that fluid does not really "wear out". Since it doesn't get hot and is not exposed to nasty acids (I guess), is why it's polymer chains hold up. I mean it lasts a very long time and you shouldn't need to change it very often unless it gets contaminated.

salad

80w90 conventional if you dunk your differentials in water, like stated you need to change the fluid if your axles go for a swim. The seals are meant to keep oil in, NOT keep water out!

75w90 synthetic if you keep it dry. Change it every few years (though if you get to playing with your Jeep you'll end up draining it more frequently... lol). Aside from synthetic gear oil lasting longer, it's not as viscous when and you'll notice a slight improvement in power and fuel economy due to reduced parasitic loss.

75w140 synthetic is called for when offroading or towing. Shouldn't be a concern for you.

Note that if you have a TracLock limited slip differential in the D35 you'll need to make sure there's the LSD additive (not the blotter paper kind). Most of the synthetic gear oils on the shelf have this already.


For a daily driver application I'd just grab a reputable brand synthetic 75w90 API GL-5 and call it a day.


Absolutely does wear out! You ever compared 10-year-old gear oil with new stuff? While our Jeep's differentials shouldn't get any more than warm, getting mashed between the ring and pinion and various bearings is sufficient to break down the oil by pure physical force. Higher shear strength is a major reason that synthetic lasts longer. (For reference, some applications actually have differential oil coolers).

Regular fluid changes are also necessary because the oil is not able to 100% prevent wear. Metal in the oil over a period of time is normal, and should be cleaned out.

DFlintstone

My book says 30K.

s346k

I changed mine and used 75-90 syn Mobil1. I used rtv. granted it's good stuff I got from a Toyota tech, what they use on oil pans etc. I bolted the cover on and filled it immediately. no probs.