Overfill with an aftermarket diff cover?

dgeist · **Posted:** Thu Dec 03, 2009 9:32 pm

I'm starting with armor on the jeep before I get a lift and my next purchase is a diff cover for the rear axle. Most (if not all) have a higher fill-hole than stock, making the "fill-to-spill" method yield a much different result for fill level than the stock cover. Also, since the shape of the covers is different, I won't be able to measure the volume precisely.

Once I get the cover, should I just fill to spill and not worry about the extra volume or will overfilling the diff case have adverse effects to performance and longevity?

Dan

RAYMAN975 · **Posted:** Thu Dec 03, 2009 9:34 pm

its not under pressure like a cars engine is. so i dont see how it could hurt anything at all. its not THAT much more fluid anyways. i have the crane cover, and filled to the fill plug where it started coming out, then plugged it up. its fine

dgeist · **Posted:** Thu Dec 03, 2009 9:39 pm

I guess the concern is with foaming/frothing the oil (as can happen in transmissions that are overfilled). I just don't know enough about how the internal components work to know if they expect to be dipped and drain on every rotation or if being submerged yields the same lubrication and wear reduction (i.e. I'm not a mechanical engineer but I worry like one

Dan

Diggerfreek · **Posted:** Thu Dec 03, 2009 9:57 pm

You get whats called splash lubrication in a diff...... I wouldn't worry about it being to over full as most of the diff covers out there are rated at almost the capacity as stock..

If you want to know more about splash lubing, let em know :wink:

tjkj2002 · **Posted:** Thu Dec 03, 2009 11:45 pm

The reason for the higher fill plug on HD diff covers is that you mostly only put those covers on for armor in a lifted rig,also by lifting you rotate the axle some(varies with lift) and thus the need for a higher fill plug to maintain the correct amount of fluid.If you overfill your diff there is not much to worry about,a little will do no harm but if you have severly overfilled it the diff will puke it out of the breather until the overfilled condition is corrected.

Boiler · **Posted:** Fri Dec 04, 2009 2:22 am

From my Riddler Diff Cover review:

Boiler wrote:

Recently I purchased a Riddler cover for my Chrysler 8.25 rear differential. Below are my experiences with it so far.

I cut out unrelated info...

4) If you fill the differential to the cover fill hole on a stock Liberty, you'll be overfilling it as I did. It accepted a little over 3.5 (!) quarts of gear oil. Today the gentleman told me that I need about a cup more than the stock recommended amount which equals a total of about 2.5 quarts. He told me the level should remain the same as the stock level for the gears, the cover itself just holds slightly more oil. They put the fill hole higher to aid in the filling of rotated axles. If you have not rotated your axle to improve pinion angle after lifting, you should watch how high you fill this. My plan is to remove a quart of oil from it with a siphon and make a dipstick out if a piece of wire, marking the level. I'll use that to check the level periodically.

If using the Riddler cover just put in 2-1/2 quarts, make an "L" dipstick and mark the level, save the makeshift dipstick and keep it full to that level. If the mechanics in the house say its ok to have an extra quart, then go for it, but you'll just be wasting $10 worth of gear lube.

http://www.lostjeeps.com/forum/phpBB3/vie ... ew+riddler

Just my experience with that particular cover.

durangotang · **Posted:** Fri Dec 04, 2009 3:04 am

tjkj2002 wrote:

but if you have severly overfilled it the diff will puke it out of the breather until the overfilled condition is corrected.

Sounds like a built in solution to me...

FILL AWAY!!!

Overfill with an aftermarket diff cover?

Who is online