So, what about the Differentials?

Saurian · #1 (**permalink**) 01-26-2004, 08:25 AM

Regarding fluids, oil and coolant are easy to drain, and I'm pretty sure that the Transfer case has a drain plug at the botton for that one, but how do you get the fluid out of the differentials? Near as I can tell, they each only have a fill hole, but no drain. Do you have to take them apart, or just pump the fluid out? I've never done it, but want to learn, as the last time I had it done, it ran me a small fortune almost equaling my car payment...

Bounty__Hunter · #2 (**permalink**) 01-26-2004, 09:33 AM

Pull the diff cover off to drain, leaving two bolts partially installed so the cover doesn't fall completely off until drained.
Clean off all silicone and reseal with RTV silicone sealant.

jay79cj7 · #3 (**permalink**) 01-26-2004, 01:52 PM

You can also pump the fluid out. It's probably not as good of a fluid change as taking off the cover, but it is what the local quick change shop would do if you paid them the 30 bucks per axle, and its easier than having to deal with removing and re-sealing the cover. You should be able to find a little hand pump for cheap at a hardware store.

graewulf · #4 (**permalink**) 01-26-2004, 05:57 PM

i bought a pump that attaches to a drill for under $15 - definitely worth it.

XJNick · #5 (**permalink**) 01-26-2004, 06:11 PM

I too own a pump. I got it from JCWhitney and it is electric. It is meant for the engine oil, but I've found it can pump the diff fluid as well ( I just don't run it for too long or it could overheat). Anyways, fairly inexpensive and very handy

-Nick

Saurian · #6 (**permalink**) 02-06-2004, 05:34 PM

Ok, I am doing the differentials tomorrow, and I am thinking about probably pumping the fluid as opposed to tearing apart the diff... I was reading on the sealant: 1 hour to harden, 24 to set up... How long does it have to sit and dry until I can fill it with diff fluid and drive back home on it? Thanks... Sean

Junkpile · #7 (**permalink**) 02-06-2004, 08:19 PM

Man if you've never changed diff fluid, then go ahead and remove the cover. Learn to do it right before you start using shortcuts. Open it up and take a look....put it on jackstands and turn it over a time or two while it's apart and you can watch it.....learn how your Jeep works.

It's also a good time to check the condition of the gears and clean out any gunk and remaining fluid that a pump won't get.

mujaman · #8 (**permalink**) 02-06-2004, 10:20 PM

just pump it out... don't bother tearing your diff apart just to look at the inside. you can go down to an advanced auto and buy a simple hand pump for about 8 bucks (they sell a few different types though... so make sure you look through them all). it takes me about 15 minutes an axle to drain it and pump new fluid in... so its a rather quick job. good luck. make sure you buy the right oil too:)

Bounty__Hunter · #9 (**permalink**) 02-07-2004, 06:46 AM

Do it right and pull the cover off to change the fluid. Clean the mating surface of the diff cover and housing real good, as well as the inside of the diff.

Slap some silicone on the cover and install it right away. No need to wait to fill with gear oil, the 90w won't make it past the silicone.

Snitty · #10 (**permalink**) 02-09-2004, 01:29 AM

i prefer to make sure there are not metal shavings laying at the bottom of the diff... there is a dimple in the bottom that can hold a lot if you don't get in there all the way

Bounty__Hunter · #11 (**permalink**) 02-09-2004, 08:01 AM

I forgot about that small sump that's cast into the bottom of the diff housing, good point on cleaning that out really well. It's a pain but it catches all the nasties.

Saurian · #12 (**permalink**) 02-09-2004, 11:33 AM

Well, I went ahead and did them, I forced the fluid out with air pressure; air goes in, fluid comes out if all is right... Bit rigged up, but it worked for the time... Next time, I'm going to go ahead and take off the cover. The only reason I did not was because I was not sure about the silicone, but since I now know that I do not have to wait a day before filling, there'd be no reason why not to... Incidentally, my fluid was dreadful... I was not sure what it was supposed to look like, but it looked like mud when it came out. With swirls, and chunks, but no water (thank goodness). And when I found that it is supposed to look like vegetable oil, I was not happy, as I had them done a year ago. Jeep's accelerating a lot smoother now. Thank you all for your help and advice...

Oh yeah, and I did find a tool that would be of great help... I did not realize, when filling both the rear diff, and the transfer case, that there is really no way to pour the fluid in, due to both the height of the hole, and tte position of the gas tank. I got this little pump, looks like what you would use for hand soap, for pumping in thick fluids and such... Got it after, would have been really handy during... But, it's a learning experience. Thanks, all, for being so helpful on this forum (