PoorMansWrangler

Hi guys,
i recently upgraded to the solid brand diff covers in my 2000 jeep xj. It has a Chrysler 8.25 rear end. The factory service manual calls for 3.5 pints, however since I have to bigger cover with a higher fill hole, I figured I would need more. I was going to fill it up until it started to leak out of the fill cap, however I am at 8 pints, and it still hasn't leaked. Should I leave the 8 pints in, drain it and measure out 3.5 pints and fill it back up? I'm feeling out because something super simple is making me super nervous. Thanks!

00t444e

Fill it up until it leaks out of the hole. Too much gear oil isn't going to hurt anything but to little will, and with the high capacity cover 3.5 pints won't fill it up enough to properly lubricate it.

XJlimitedx99

Worse case scenario, you overfill it and it leaks a bit out of the vent hole and/or axle tubes until its at an acceptable level. The higher fluid capacity is better because the heat generated from the gears will be distributed to a larger volume of fluid. Less fluid would not reach high enough to properly lubricate.

bad_idea

Contact Solid.

If the placed the fill hole at a higher point, they did that for a reason. I don't know what it may be though.

To parrot what others have said, it won't hurt anything to over fill it. Just makes a mess until the fluid leaks out to the necessary level. I have been dealing with that in my 8.8 in the back of my XJ. I tipped the axle up, pointed at the TC for a double cardon shaft, and now the fill hole is much higher. I fill it till it pukes out the fill hole, then it spends a couple weeks spotting my driveway until it pukes out what it doesn't want.

tech

Just look at the old cover and see where the oil level is then just make a dip stick so you can tell when it full . I would add a little more just to be safe .

XJlimitedx99

The fill hole is often higher on aftermarket covers to compensate for a greater pinion angle on many offroad vehicles.

aka"dude"

This and the one about if it is over filled it will just push the excess out the breather tube. Messy but atleast you know you got enough in.

Dig'sXJ

I just did the same cover on my XJ and was wondering the same thing, when I found this thread. Old thread, but was wondering if you ended up filling it to just below fill plug? And if so, how did it work out? Any noticable issue? Thanks

XJlimitedx99

On my 8.25 with a Solid cover I've gotten into the habit of filling until I can reach my pinky into the hole and touch the fluid. So, just below the fill hole. I also switched to 75W-140 weight oil because I once had the fluid overheat/foam and spew a bunch out of the breather. The factory service manual calls for the 140 weight oil under "severe" usage. I have had no issues with this method.