Have a 95 aero E4wd. Have replace driver side cv axle and drove about 8 miles then the outer joint broke. Had mech change cv axle and drove about 2 miles and the inside broke.. Same mech replace it and drove 3 mile and heard like rubber on metal like a flat tire. The cv axle did not break and wont turn when in gear. Back to shop with aero.
lifted on lift and jacked up front and rear. Turned the driver side and the passenger turned with it also it turned easy. Started it up and placed in gear, all were rotation except driver side , it was hung up.

any clue on what should be fixed on diff?
trying to save some $ on it alread went tru $600 in a 3 days for towing and 3 cv axles + labor

 

Definitely something is wrong with the diff.
There must be an excessive freeplay due to worn bearings and/or gears and something jams against something when horizontal forces act on the axle (like around corners) The diff temporally seizes and the resulting stress breaks the weakest part which is apparently the after market (I am just guessing) CV shaft joint.
I would peek into the diff before waste another CV shaft.

 

well I am getting a used diff for $200 or if the mech can get one cheaper.
I am going to keep the old one to check out and be fixed by self.

I paid $800 for the aero and new it was worth much more. Has one rust spot on paint behind driver door and right rear bumper from corner to tire is gone. inside and out is in great shape and well taken care of. It just pisses me off cause I knew nothing of about AWD systems , this fourm is a big help.
after all said and done I will have around $1200 into it.

 

Once you will get it right you will find that A-Stars have an excellent AWD system. It is not for extreme 4x4 stuff but they are unstoppable in snow and mud. Just look at my avatar. 2 feet of snow and the only issue I had that the snow was getting pushed up to my windshield blocking my view.
I made that pic when I was trying to free my semi tractors from the snow by breaking a trail for them with my van.

 

I have to echo this claim of mobility in the Aerostar. One time I was skiing (what I originally bought the van for) when several feet of snow were dumped during the day. When I got back to the parking lot, there were snow drifts over 3 feet tall all around, and the lot itself must have at least 2 feet of snow over it. I was able to just gently back my van out and over its drift and get on my way. I saw at least two Suburbans that got stuck in the parking lot, with all 4 wheels spinning helplessly through the snow, digging themselves deeper, and about 8 guys each trying to push them out.

 

My AWD system was not fully working (transfer case won't lock), but despite that, I went to a storage unit after a big snowstorm. A crew was plowing the units and had piled up snow about 4 feet deep in the center of the aisle. As I went to leave, the guys told me how to get out by going around to the other end, but the gate was closed, and the controls were on the other side of the snow pile. So I ignored their warnings, and drove right over the snow pile and got the gate open and left, with both the morons who were working there with egg on their faces. They were convinced I would get stuck cause they had to pull two other cars, a Silverado Pickup and a Jeep, out of that same pile. My not even fully operational AWD system could handle it better.

 

page 144 on OEM manuf. for Ford

http://www2.dana.com/pdf/X510-9.pdf

Aeros go well in the snow. even weight distribution


had to clean the snow out of the grill and radiator several times that day

 

well I opened the diff up and saw nothing loose nor damaged.
all gears look fine including teeth on left & right shafts.
How cant I tell if a bearing is bad? (they seem to flow in same pace with same gap)

got a used one and is in place but just waiting for cv axle.

what else could it be if it's not diff?

 

It's starting to sound like there were problems with your replacement CV shafts. After you assemble the new parts, and before taking it out again, run it jacked up off the ground to make sure all wheels turn. With the engine idling, you can try to hold one of the front wheels steady, and the other should start spinning twice as fast. Then do it again with the other.

The other thing you might try is to disconnect the AWD computer under the drive's seat. This makes the center diff run in completely open mode. I've had that thing lock up when it's not supposed to, and it really sounds like it's going to break an axle or something. In my case, it was because the front and rear tires had enough of a difference in diameter that the computer thought one was slipping when going around low speed corners. I run in the open mode all the time now, and I figured that if I ever get into a condition where I need the center locked again, I'll just connect the computer up again.

 

This reminds me, ever since I replaced the ATF in the front diff with 75w90 gear lube last year, I've had a pretty steady pukage of lube from the vent tube. This happens during long drives, where the diff has a chance to heat up from running. I'm sure I installed the right amount of lube after draining the ATF, so I'm thinking the much thicker is getting too hot and expanding out the vent hole. I also wonder if the thicker lube is able to get into all of the bearings properly.

For those who have done this, what are your experiences?

 

well I had the hub replaced and a more durable cv axle from NAPA.
All is good for now...

gear oil will take longer to heat up. When it is super hot it will flow like hot vegetable oil and expand some. Your bearings are in oil soup at this point and has some friction.

how much does it call for? and was it bone dry before add oil?

 

being running 75w90 Amsoil Extreme Gear PAO synthetic in my front diff for several years
no problems and runs cooler to the touch especially towing

I used to tow 4000 lbs+ with it in Cascades, 101, east of the mountains summer desert and Rockies
no noted problems. checked it before I towed last. clean and no cuttings.
no boil out the vent tube here.

just a small amount of that sulfur laden diff lube smears around a long ways.
like blood, drop looks like a gallon.

how hot is your diff getting? i can hold my hand against mine, hottest towing was probably 150ish D F

now you've got me thinking, i'll put the infrared thermometer on it this summer in the heat.

 

Congratulations Ford Driver. Hopefully the new parts will last longer.

I drained out the old ATF before filling it with Mobil 1 synthetic gear lube. I don't tow, and After a 75 mile drive today, I smelled the burning gear lube, and saw it dripping from the vent tube. It's been a year since I did the change; it spewed immediately afterward, and I thought it was just boiling off the extras. It has been doing it periodically since. I can't remember what capacity was the spec. I haven't measured the temps, but it keeps spewing for whatever reason. I'll have to put my thermal sensor on it after the next long drive and see.

 

all I know is that the capacity is 1/4" or 6mm from bottom of filler hole..
any closer to the hole it will be to much and leak out..

 

The oil comes out when the vent is plugged. Pressure builds up inside the axle and eventualy pushes out the oil. It can be quiet severe on big rigs.
Gear oil is much better in diffs, transmissions or in any kind of gear boxes. Auto trannies needs ATF due to the valves, bands, and the torque converter. ATF is a compromise between hydraulic oil and gear oil. Not as good against wear as gear oil that is why manual trannies last 3 time longer than autos.
Of course both my rear and front diffs are filled with Chevron gear oil.