I would like to change the front diff oil on my Aerostar but it doesn't look like there is room to remove the cover without dropping the diff.

Is this easier than it looks?

Also Ford runs ATF for lube in the diff which seems kind of light to me. Has anyone changed to gear oil for the front diff?

 

Just changed my again on my 93 Aero. I used a little sucker pump for fluids you buy at the auto parts place. Put some small clear hoses together where the finale hoses are smaller than a pencil. Insert & pump it out. Reverse the process to put in new. Gets out 98%. I meassured what came out. The book says 2.2 pints & that was what I got out.

 

I did the same as Avanti on my Aerostar and BIIs. Suck it out and put it back in with a small hand pump. If you have an AWD you really should do it every 30K or so because the repair for the front diff. __IF__ it goes bad can cost upwards of $1500+.

Almost all of it labor from dropping the front axle from the van.

 

Do as Recarbo and Avanti advise.

If you try to remove those large single nuts that secures the diff to each rubber isolator, you run the risk of coring the mount and ruining it. There is no "head" on the bolt, as the shaft is molded into the rubber isolator and the amount of threadlocker used to secure the nut almost guarantees the rubber will shear before the nut comes loose. You can remove the two smaller bolts that hold the isolator to the frame but the ones above the differential are hard (to impossible) to reach.

The mounts are pretty expensive to replace. If you must remove the large nut, heating it briefly with a propane torch to soften the threadlocker will make it much easier to remove.

 

I need to change the oil too. However, who ever filled it up last used gear oil instead of ATF, so I'd like to drop the front diff assembly to clean it out thoroughly. I also noticed that a small bracket (2" x 2") that secures back of diff to the isolator mount is cracked completely through. It is secured on one end with one of those large single nuts.

I have the OEM Ford CD that shows how to remove the front diff assembly. The first part is of the procedure is very straight forward - you simply remove the inboard CV joints at the flanges and tie them up. Then, it says to remove the 2 smaller isolator nuts like aero decribes from each mount.

My question to anybody is - are they accessible? I don't have a lift. Any tips from someone who has done this?

Also, I think I'm leaking grease where the left inboard CV flange and diff flange bolt together. At first I thought it was the CV boot or axle seal. However, an inspection revealed that the boot was intact and that the axle seal was dry externally. All of the oil/grease is coming from where the flanges meet. Dropping the front diff involves unbolting these flanges, so I could inspect things further.

Any other possible causes here?

 

Here are 2 diagrams.





This is the bracket that's broken. Ford wants almost $50 for that little piece of metal!!! The rear rubber isolater appears trashed too.



This is the front of the bracket (different) that bolts to the diff with 2 bolts. I want to take these two bolts out instead of the individual isolator nuts. What do you think?



This is the rear of the same bracket showing the second bolt (bottom of pic)



This is the driver's side inboard CV joint that I think is leaking grease. Could grease leak like that after it was warmed and turned with the axle? What do you think?

 

Hi Areyou4real:

Somehow, I can't see the picture you posted. If I can see the pictures, I may be able to help since I did take my differential apart recently.

 

I don't know why they're not working. You can see them 1-by-1 here:

http://pg.photos.yahoo.com/ph/anoriginalid/my_photos

 

It's the Yahoo! photo hosting, it looks like they don't want other sites using their bandwidth, but they don't mind if you come to their site (and see their advertising).

 

Rather than a small pump, like this POS I have (do NOT buy one of these, you'll be sorry!):



I can recommend this one, which I also own and which I use all the time.



It's larger than this picture implies, about 2' high, and it really, really works well, I can't recommend it enough. I've used it for gasoline, diesel, ATF, PS fluid, coolant. Though not shown very well, it comes with three 4' long nylon pickup tubes (you can just make out the adapter ends in the foreground, but since the nylon tubes are the same white color as the pic's background, they're invisible. Dumb photo composition.). Holds about 1.5 gallons and has one-quart demarcation lines on the reservoir, so you can tell how much you've removed. Easy to empty (remove a stopper on top, and dump it).

It's not as cheap as the little hand pumps, but if you need to use it more than once, it's well worth the money. I used mine yesterday to R&R the old gear oil in a '68 Dodge PU -- gear oil takes longer, but you just pump the vac's handle a dozen times and walk away, it works slick. Later, I came back and sprayed a bunch of Brak-leen into the diff's fill hole, then sucked that all out. Best you can do without teardown.

Use it to change out the black PS fluid! If you jack up the front so the wheels move easily, you can vac & refill the PS pump, start the engine, cycle the steering wheel back and forth 30 times, shut off engine, vac & refill . . . do this four times, and the fluid looks really nice & clear again, and you've spent less than $10 for all the fluid (I prefer to use real PS fluid as opposed to ATF, but for no good reason).

Anyway, I didn't think I would, but after using it I really like this tool.