I had to pull the diff cover the other day to take some measurements and decidedd to change the oil while I was in there. Not thinking I bought some 80-90 G/O.

I just looked in my Haynes and it calls for 75-145 synth. What's the worst that could happened with the 80-90 in there? Is this synth that much better? Any comments would be appreciated. Any oil experts out there?

I don't want to pull the cover again since I did such a nice job sealing it...LOL. If it has to be changed, it has to be changed.:banghead:

I went through a similar experiance..
Canged gears in my X to 3.73's from 3.27. The owners manual stated in a footnote that 3.73 and 4.10 x's use 75W140 Synthetic....I had put 80W90 Mobil 1 in.
Because I tow, I went with what Ford recommended and dumped out the 80W90.

The only place that had the 75W140 was FORD at $17 a qt (retail)

I think I even towing would have ben OK with 80/90 but it seems the manufacturers are leaning towards the 75W140 synthetic for some reason...

Kurt
97 Explorer Sport

for some reason 80/09 doesnt sound good... i think it may not allow enough cycling of the metal....also, do you have a lsd? if yes then change it out and put friction modifyer also

It is factory open..I do not have LS.

Purple, stop going to Ford to buy stuff. They see us coming and jack the price.:eek:They gave me that BS story too about it being SO expensive. It's $3.49 a quart(75-140 Synth) at Pep boys and Advance Auto.

Thanks guys...

The stuff at Pep Boys and Advanced Auto is not synthetic, I tried every parts store around and could only come up with a synthetic blend by Valvoline so I went to Ford for 100% synthetic.
It isn't really a rip off, it is 17.49 retail, 15.50 wholesale, they arn't making much money on it, I think it is made by Amsoil, if you were to go out and by Amsoil, it would cost you what the Ford brand would.
(...remember the Mobil 1 80W90 is $8 anything cheaper than that would not be synthetic


Kurt

OK, I see what you're saying. THe Ford dealer here said it was a blend, that's why I looked for it somewhere else. If it is a full synth then might as well get it at Ford I guess.

So, does anyone have any ideas on the effects of 80/90 over synth 75/145?

I need to know too. I used 80/90 syn in my front diff today and now I have a bad vidbration when turning. The steering wheel shudders (sp?). I also changed transfer case fluid today, but that is just ATF and I used a synthetic there too. Maybe my vibration is from the front diff not working properly and not allowing the wheels to spin freely from each other? Would the wrong wheight oil do that?

I did nothing else so I cannot figure anything else that could be causing that?

Nah, 80/90 wouldn't casue that. The wheel shudders? Explain it.

I was reading in my Haynes and it says that ALL explorers use 75-145 synth diff oil. I find it hard to belive that even back at the beginning they were using that stuff.

by shudders I mean when I turn the steering wheel vibrates back and forth like it wants to snap my arms off. I don't know what else could cause it. All I did today was change fluids. I also changed the transfer case fluid and put in Mobil Synthetic ATF. But according to the guys at the auto parts store Mercron is just standard ATF so that should be fine, right?

Is there a way to find out if that fluid is causing those problems?

Did you spill oil on the belt by chance?

what belt? The fan belt? I doubt I got any fluid on that.

is there play in the steering column under the hood normaly?

what do you mean by play? play in rotation, yes. PLay back and forth, no.

I meant the serpentine belt, it powers the steering pump.

I'll check the belt, but it looks like it is on the main belt? and I don't see the serpentine belt in the manual?

Play I mean if I grab it I can pull it up and down in relation to the ground, and see the steering wheel vibrate.

Hay, check this out.

http://intershop.amsoil.com/cgi-bin/Amsoil.storefront/3cb8d7810230b30c271bd1f0e3f00710/Catalog/1156

Originally posted by 2001ExpSport
I was reading in my Haynes and it says that ALL explorers use 75-145 synth diff oil. I find it hard to belive that even back at the beginning they were using that stuff. They didn't use that to start with. I was at the dealership recently, a dealership that I actually TRUST the parts department (friends of the family), and found that Ford has changed specifications on all the Explorer rears to use 75W-140 synthetic. I believe all fronts call for 75W-90 synthetic, but I can't remember if that's right or not.

Originally posted by taxxman2k
I'll check the belt, but it looks like it is on the main belt? and I don't see the serpentine belt in the manual?

Play I mean if I grab it I can pull it up and down in relation to the ground, and see the steering wheel vibrate.

Uh, up and down in relation to the ground...no.

There is only ONE belt. Haynes book 36024 1-15 ;)

I just orderd 4 qt's of 75-140 from Amsoil @ $12 per qt. Even with shipping it's cheaper than dealer.

http://www.amsoil.com/products/prodpics/tgo.jpg

HECK YA!!!! Amsoil rocks!!! Good choice. I got 4 of those in the box ready to go in my front and rear diffy. I already installed the Engine oil and trans fluid, and its really nice. I posted about the engine oil in another thread in general explorations.

WTF! I called my dealer and the service dept told me 80W-90 Non Synthetic!

Another non Ford Service center told me 80w-90.

Another Ford told me 80w-90

Why is everyone getting a different story?
And if I used 80w-90 synthetic will it hurt since everyone is saying non?

Thanks guys

Front axle (dana 35 or the Sterling-Van Dyke variant) gets the 80w90. Synthetic won't hurt it. The rear axle fluid depends on the year, gear ratio and carrier type. My 2001 XLS with a 8.8, 3:55 open rear calls for 75W140 Synthetic. (there is a tag on the rear axle that says this).

The shudder in the steering could also be caused by air in the power steering system. With the power steering fluid full, cycle the steering full lock to full lock several times (with the engine running). That will bleed the system if there is any air in it.

Thanks I am leaving the 80w-90 Synthetic in the front. The shudder went away on its own. After I played with it for a while.

I got regular 80/90wt in my front and rear diffs of my 91 Sport. Never had any problems.. Front is open, rear is L/S but, that is shot, so I didn't throw any of the l/s additive in there... But I don't know if ya are er aren't... Oh well, it'd doin fine.
Pete