REAR end FLuid replace

[1_v8_merc]

Arent there already like 1000 detailed picture filled posts on how to do this procedure?

I've done it before on a mustang, piece of cake.

The real shocker is if you DONT find a gasket underneath the rear-diff cover,lol, that actually happened to me.
(i was thinking "what the hell was this guy thinking when he did this.....)

 

[Pontisteve]

The 02-05 Explorers have IRS, so it's a slightly different game than on a solid-axle Mustang. But it isn't much harder.

BTW, the factory often does not use cover gaskets anymore. They just use silicone instead. It seals better, and doesn't leak as it gets old, unlike cover gaskets.

 

[LVmounty]

So is there a drain hole on these diffs or do you have to remove the diff cover to drain it?

 

[jasongt06]

it has a drain and fill hole on the cover.

 

[Pontisteve]

The diff cover on the IRS acts as a mounting point for the rear end. You cannot remove it without some serious labor involved. Just pull the 2 plugs in the diff cover. Make sure you pull the top (fill) plug first, because if you drain it first, and then discover you can't get the top plug out, you're screwed.

The top takes a 3/4 square drive, and the bottom a 3/8 or 1/2 square drive. I just used a 1/2 to 3/4 adapter, and a 1/2" drive breaker bar.

Be sure to teflon tape or teflon paste the fill and drain plugs when you put them back in, so they don't seep.

If your truck has a posi, then you need to add the posi lube as well as the gear oil. The gear oil was changed by a TSB to 75w140 synthetic, so use that.

 

[alexk]

I went to the dealer today to get a list of what maintence I needed and I told him I wanted the differential fluids changed and he told me dont bother with them until 150K just do the transfer case. I should just get those fluids changed anyway right? Im at 95K now.

 

[Pontisteve]

According to Ford, it's filled for life. In other words, no maintenance. This is the same Ford that says the gear lube in it should be changed to 75w140 over the factory 75w90, because there were complaints of premature failure or whine. Your call.

While I know rear ends don't need maintenance often, I figure it like this: the average life expectancy of a car is probably around 200k. After that, most people aren't likely to want to drive it anymore, and it rolls down to the lower end of the economic ladder to drive. So think of it as changing the fluid just once in the life of the car... and why not do it at half-time?

You should also have a hard look at the rear axle seals, where they press into the rear end housing. They're known for leaking, and have had about 5 different revisions until they finally came up with a seal that works. I switched mine (along with a ton of other work at the same time), since I was in there anyway. Point being, if the axle seals leak any considerable amount of fluid, then you don't want to go 100k between fluid changeds or fills, if you know what I mean. Same goes for the front (Pinion) seal.

BTW, those jobs mentioned are not easy homeowner-type jobs.

 

[alexk]

Well Im having my mechanic change my transmission fluid Tuesday morning so Ill have him take a look. I also mentioned about the while at ford and he said "oh its probably just a bearing, Ill get you a price if you want" I passed.

 

[marks69cruiser]

I am going to replace my fluid tonight. Hopefully that will cure my low speed lurch/bang!! I will let you know. 2002 v8 explorer with the IFS.

 

[clarks2001]

How much gear lube and friction modifier does it take to fill up the rear differential? I have the D4 code....3.73 Limited slip i do believe. Plan on changing the lube to see if it does away with the hum/grind noise. Pep boys told me my axle bearings are going bad but I figure it should be fairly cheap to try changing out the lube to full synthetic

 

[EasyRhino]

How much gear lube and friction modifier does it take to fill up the rear differential? I have the D4 code....3.73 Limited slip i do believe. Plan on changing the lube to see if it does away with the hum/grind noise. Pep boys told me my axle bearings are going bad but I figure it should be fairly cheap to try changing out the lube to full synthetic

I think it's about 1 1/2 quarts or so. Anyway, you get to buy two quarts worth and just fill it up to the top off point.

Mine has the hum, but no grinding noise, good luck with that.

I do not understand the comment on axle bearings going bad. Do they mean the wheel bearings, the axle shafts, or the read end carrier bearings? Curious to know how they could figure that out.

 

[clarks2001]

I think it's about 1 1/2 quarts or so. Anyway, you get to buy two quarts worth and just fill it up to the top off point.

Mine has the hum, but no grinding noise, good luck with that.

I do not understand the comment on axle bearings going bad. Do they mean the wheel bearings, the axle shafts, or the read end carrier bearings? Curious to know how they could figure that out.

Well it is pep boys lol. I didn't understand it myself. I am just gonna change fluid to full synthetic with friction modifier and see if that helps. It's a fairly inexpensive gamble that I'm willing to try. The wheel bearings are fine. And the axle shafts look like they are fine from what I could see. Don't know about the carrier bearings...hope they are good. Doesn't sound like a cheap fix lol

 

[EasyRhino]

Well it is pep boys lol. I didn't understand it myself. I am just gonna change fluid to full synthetic with friction modifier and see if that helps. It's a fairly inexpensive gamble that I'm willing to try. The wheel bearings are fine. And the axle shafts look like they are fine from what I could see. Don't know about the carrier bearings...hope they are good. Doesn't sound like a cheap fix lol

Lots of folks get so worried about the whine that they feel compelled to do major surgery on the diff. But you can go many many miles as long as you can stand the whine and it doesn't get worse.

Changing to thicker oil is far cheaper than a rebuild. Good Luck.

 

[SCCA_Racer07]

I went to the dealer today to get a list of what maintence I needed and I told him I wanted the differential fluids changed and he told me dont bother with them until 150K just do the transfer case. I should just get those fluids changed anyway right? Im at 95K now.

I don't understand why the dealership would tell you this when it is there goal to make money.. Sounds fishy

 

[clarks2001]

Lots of folks get so worried about the whine that they feel compelled to do major surgery on the diff. But you can go many many miles as long as you can stand the whine and it doesn't get worse.

Changing to thicker oil is far cheaper than a rebuild. Good Luck.

Well, I DO got a stereo system... so droning out the noise is easy haha. Still going in for a second opinion and changing fluids regardless. Its about time to get the full synthetic treatment in the explorer anyhow

 

[abbyroadkill]

thank you all for the great replies and help

 

[bigred1]

code question

Howdy my axel code is 45 so it should be an open diff but if I peel out I get two marks( on damp pavement). How come shouldnt it be only one. I have a two wheel drive 2002 with V8.
thanks
Rod

 

[Pontisteve]

That can happen sometimes. Centrifugal force, I think. Try getting in a little sand and give it a light spin, and see what happens. Or better yet, jack it up in the back and turn one tire forward. If the other goes forward too, it's a posi. If the other goes backwards, it's an open diff.

 

[PC]

Why synthetic fluid?
Is there a legitimate reason or do the Ford bean counters just want more beans?

I just did mine today, but did not use a synth and I dont really want to do it again

 

[RickM]

I am going to replace my fluid tonight. Hopefully that will cure my low speed lurch/bang!! I will let you know. 2002 v8 explorer with the IFS.

Sounds more like the solenoid packs. How did things work out?