Replacing Rear Diff Fluid

[girthsr]

I have an '03 2wd with the whining, howling, grinding in the rear differential that seems to be pretty common. I have decided to replace the oil and add the friction modifier as a starting point. I have all of the supplies, but when I climbed under the car, I noticed that the drain plug takes special 4 sided wrench. I was thinking about trying to siphon the oil out of the differential by way of a hand pump, although I have no idea if this will work. Does anyone have any suggestions on how best to change the oil in the rear differential?

 

[IZwack]

The "four sided" wrench :

Often used with an extension if not long enough:

 

[Hyper26414]

The "four sided" wrench :

Often used with an extension if not long enough:

I don't care who you are that's funny right there!!!

 

[xlt03]

The fill plug takes 3/8" as pictured. The drain plug is 1". You can use a 1" to 3/4" adapter on 1/2" drive.

 

[rumpledoll]

Before you remove the larger bottom drain plug, make sure you can remove the upper smaller fill plug - it's harder to remove. There are a few stories on this site of trucks towed to the dealer/shop because after removing the large fill plug and having all the gear oil drain out, the upper fill plug couldn't be removed and hence no fluid could be put back into the differential. I used a long fixed breaker bar to get the necessary torque to remove the smaller fill plug.

I have a 2002 4WD V6 Eddie Bauer with the limited slip rear. I tried using Lucas Synthetic 75W140 gear oil but the friction modifier in the oil still left the rear chattering during turns and the rear was a bit noisy, especially at speed. I quickly switched to Amsoil Sever Gear Synthetic 75W140 oil with an additionally 4oz of the proper friction modifier and this fixed the chattering on turns and the diff is quieter than it ever has been at highway speeds. Like night and day compared to the Lucas. Recommended.

Rumple

Does anyone have any suggestions on how best to change the oil in the rear differential?

 

[MrQ]

I don't care who you are that's funny right there!!!

Sick man.

Anyways, make sure you have a big enough pan to drain the fluid. Siphoning it by hand without a good pump could take a LONG time. Believe me. I just recently replaced my dif oil and i had to pump a whole two bottles back in by hand with a gravity pump. Not fun.

 

[993usmc]

The drain plug is 3/4" on mine. I bought an adapter for my 1/2" ratchet. I just refilled it with Mobil 1. Too easy.

 

[Hitchhikingmike]

I had no problem getting out the top fill plug on my 3rd gen rear diff. It was the bottom I had trouble with. I had to put the explorer on jack stands so my long handled wrench would fit. I then had to take the rear passenger wheel off so I could wrap a tow strap around the wrench and pull on it with help from 2 of my other buddies about 6 feet away to get the plug moving. It was like playing tug of war.

We had to put close to 400 ft/lb of torque on my bottom drain plug to get it out.

This is the ratchet I used.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=31702

it is a HUGE ratchet, and I still couldn't get it out by myself.

 

[jmorristn]

did changing the fluid make the whine go away?

 

[estell]

I put in Redline 75W140 and the low-speed chatter did not go away. Then I added 3 ounces of Amsoil friction modifier (spilled 1 ounce) and the chatter was reduced by about 3/4ths. Someday I'll add a few more ounces and get rid of the rest of the chatter, but it is tolerable now.

 

[jmorristn]

did the "whine" go away like at 55-60 mph when touching the gas pedal?

 

[estell]

My Mounty never had the whine.

 

[Oldwolf]

Getting ready to change the fluid in my 02 Exp with LS rear end.

I noticed that Mobil 1 already has the friction modifier in it. Does it have enough or should I go ahead and add the XL-3 friction modifier?

Also saw that Autozone has CRC friction modifier for LS diffs. Is this an OK product or should I stick with the Ford XL-3?

Thanks.

 

[ej76623]

im also changing mines, but can't find a tool to remove that 1" drain plug... any ideas?

 

[jmorristn]

you need a 1/2" drive to 3/4" drive adapter to fit the socket wrench. autozone has them about $5.

 

[thepotroast]

im also changing mines, but can't find a tool to remove that 1" drain plug... any ideas?

3/4" ratchet, or an adapter to fit your 1/2" ratchet to give it a 3/4" head.

I bought mine from Autozone....they are $7.99

You can get them cheaper, Harbor Freight has a 4-adapter kit for like $5 that has this adapter in it.

 

[ej76623]

wow thanks for quick reply, going to autozone now to get that adapter $5.99 thank you very much again

 

[thepotroast]

wow thanks for quick reply, going to autozone now to get that adapter $5.99 thank you very much again

I seriously have the receipt in hand when I purchased my 1/2" to 3/4" adapter from Autozone for $7.99 grrrrr, I feel jipped!

Must be a regional thing

 

[alexk]

I don't care who you are that's funny right there!!!

I dont get it:scratch:

 

[Hitchhikingmike]

im also changing mines, but can't find a tool to remove that 1" drain plug... any ideas?

oops, i already said that in my previous post