Riddler diff. Covers. Fluid should be filled to spec. Even with larger covers. There is only that much fluid in there for a reason

 

To me it just looks out of place on a XJ, but they are beefy as hell

 

Looks like they made the mounting ring way too wide for what is needed. The D30 solid cover is amazing in looks and performance. I've been bashing mine for 5 years now

 

Thanks for all the replies guys. Just to give an update on things, I decided to stay with the factory diff cover. I removed it cleaned everything up and repainted it. I used the Lube Locker gasket and replaced the fill plug with a new one. I used 75w-140 fluid and filled to spec. So far so good. No leaks yet!!

 

Well painting it is the mall crawl/club xj life bro!

 

I recently installed a SOLID cover on my 8.25 and filled it with 75W-90 to the fill hole. It took 1.5 gallons of gear oil to fill. I could not believe it kept taking more. I took the Jeep for a trip through the mountains and was pushing it pretty hard for hours. It heated the fluid enough to push a large amount of fluid up through the breather and into the unibody rail. Enough that there was a large puddle of gear oil on the ground.

In hindsight I should've ran the 75W-140.

 

Both diffs total don't use that much fluid. Let alone just the rear. 8.25 rear uses 4.4 pints.

 

I just filled it till it came out the fill hole, like I've always done with the OEM covers.

 

That is the thing I asked earlier in the thread.
The fill holes in the aftermarket ones look higher then a factory one.
So when you first make the swap you know how much to put in.
4.4 pints in an 8.25.
But how do you know where it is at when you want to just check it when you change your oil?
See I don't understand the logic behind this.

 

That's cause it is a mall crawler for now.

 

The other thing that concerns me with that logic is if the cover is any "deeper" than the OEM cover the fluid level will not be as high.

This might warrant a call to SOLID tomorrow..

 

[QUOTE=00xjfreedom;3560325]This is a good watch on diff covers..

I hope everyone that has or is considering an aftermarket differential cover watches the videos that 00jkfreedom attached. And good call by Ralph77 to question the level of fluid with aftermarket covers. In the videos Banks did a nice job of questioning some aftermarket cover designs. He pursued data, going beyond looks and perceived notions of what works better or is “cool” and did testing to show what modifications from factory cover designs might mean to the differential. Changes in fluid level and lubrication paths can have significant unintended consequences. As pointed out increased temperatures and oil aeration can occur with cover modifications, both which are not favorable for lubricating highly loaded hypoid gears. Entraining air a lubricant can degrade its ability to maintain fluid film and thus provide adequate lubrication. The engineers that designed covers for the OE differentials would have used past lessons learned, results of analytical tools such as fluid dynamics and thermodynamics and test results as inputs to the design. This level of product expertise, engineering analysis and product endurance testing are likely not available to most of the aftermarket manufactures and it is expensive and time consuming.

If most of the use of a Jeep is rock crawling at low speeds then a heavy duty differential cover probably make sense. For the other 99% that are driven at highway speeds there is the risk that an aftermarket cover is doing more harm than good. OE differentials are pretty darn reliable as they come from the factory. Why spend money for something that likely isn’t needed and may shorten the life of your differential?

I had considered changing covers. After seeing this thread and doing some research I will stick with factory covers or those that very closely mimics the factory cover design.

 

The problem was likely aeration. The lube was full of air. As air gets entrained in a fluid it increases its volume and generates foam. There is only so much room in the differential so it is pushed out of the vent. I doubt that a different fluid/viscosity range would have made much difference.

 

And that is something I did not think about.
I have never seen an aftermarket diff cover up close and personal.
I am just going by pictures I see when I say the fill hole looks higher.
Thinking cause you got so much gear oil in that I might be right.
I would consider one with both a fill hole and drain hole.
My '00 XJ is just a DD. So it would just be for a look but I would justify it as for maintenance too.
I am big on swapping out fluids on a regular basis.
I dump my tranny fluid every other year.
Why? Cause Jeeps have a drain plug. For the price of the 4 to 4 1/2 quarts it takes when I do this is fine with me.
It is easy to do so why not.