Filling my Ford 8.8 (gear oil out the vent tube).

[TerryMason]

So I've been chasing what I thought was a leak in my new Ford 8.8 rear axle, and finally chased it down the oil coming out of the vent tube, which tells me that I've overfilled the axle.



The axle was filled using the front (factory) fill plug. When I remove the plug and stick my finger in, the oil level is to low for me to reach (let's say 1" under the fill plug). Should I pull some fluid out, or just let the extra kickout the vent tube?

 

[SteelHeadz]

I would pull the excess out . If you just let excess fluid just spit out the vent tube, it's still not accurately within the specified level.. The excess fluid will cause aeration and damage the gear mesh surface and bearings..

 

[TerryMason]

Thanks Mikey. I think the problem is that my axle pinion angle is higher than stock, so what would be the factory fill line is not accurate any more. I'll probably pull out 1/ to 1/2 a quart and see if that fixes the problem.

 

[SteelHeadz]

In that case, i would research the factory fill fluid qty. and fill it that way. If the pinion is nosed up higher than the fluid level, then i would add just enough that the pinion bearing can pick up the lubricant to rotate on the upper section of the bearing as it rotates.

Thanks Mikey. I think the problem is that my axle pinion angle is higher than stock, so what would be the factory fill line is not accurate any more. I'll probably pull out 1/ to 1/2 a quart and see if that fixes the problem.

 

[TerryMason]

That's a good call on just putting in the amount the manual calls for. I'm using synthetic, so the stuff is close to $20 a bottle.

 

[SteelHeadz]

I wish you lived closer to me. I could give you all the synthetic 75w/140 you need.

 

[stumblnyj]

I wish you lived closer to me. I could give you all the synthetic 75w/140 you need.

Them Texas boys and their oil. LOL

 

[TerryMason]

For anyone else looking to fill their 8.8, it looks like the Ford Explorer takes 5.5 pints of fluid. I'm going to drain my diff and refill it with the proper amount of fluid. I believe that I put an extra 2 pints in mine.

 

[TerryMason]

To add a bit to this thread, I've got the Solid brand diff cover, which changes the capacity a bit. I called and talked to the guys at East Coast Gear Supply (very helpful), and they mentioned that the capacity with this cover installed is right around 3 (quarts I assume).