Diff capacities wrong?
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JK Enthusiast
Joined: May 2007
Posts: 311
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Diff capacities wrong?
OK, I did search and had no luck. It's probably here somewhere but I can't find it so here goes. I just got some Riddler diff covers (VERY nice I might add) and installed the rear tonight. The fill hole is much higher than stock so I made a dipstick to measure the fluid at the same level as the stock hole. The FSM says the D44s take 4.75 pints rear and 2.7 pints front. Well I put 2qts Royal Purple in the rear and checked and it's already at the level of the original fill hole. WTF? Is the manual wrong? I know others have installed these covers so please tell me how much you used. I don't want to run it too low but I sure don't need it venting out all over either. Thanks.
JK Enthusiast
Joined: May 2007
Posts: 457
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From: Boise, ID
I would suspect that different covers will change the volume in the diff and thus require different levels of fluid to keep the same ratio of fluid:empty space in the diff. Hopefully the makers of the covers engineer the fill hole position to be in the correct spot so you can fill it to the hole and have enough fluid in the diff. But it is 2:30 AM and I dont know much right now :P
JK Super Freak
Joined: Oct 2007
Posts: 1,095
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From: Raleigh, NC
The capacities will change since the differential covers are contoured slightly different to increase structural strength. Some after-market covers increase the oil capacity, others may decrease it.
From what you are saying, the oil capacity didn't change drastically.
4.75 pints = 2.375 quarts
If the rear only managed to take 2 quarts of Royal Purple, then the capacity only decreased by 3/4 pint, or 3/8 quart - not a huge amount.
Make sure you are on a level surface when you pour the oil in the fill hole. Fill until the oil level reaches the level of the stock hole. You can hold the stock cover up to the new cover to gauge more or less where it should be. Make sure you do not overfill because the oil may spill out from the breather tube and make a stinky mess everywhere. The operative words being "stinky" and "mess". If you feel that it is insufficient oil at first, drive your Jeep around the block once to let the oil settle and eliminate any possible air that may be trapped anywhere. Re-check the levels and add oil if necessary.
Wayoflife did a great write-up of the Solid differential covers install where he addresses the oil fill levels. Check it out:
http://project-jk.com/jeep-jk-write-...r-installation
Hope this helps and good luck.
From what you are saying, the oil capacity didn't change drastically.
4.75 pints = 2.375 quarts
If the rear only managed to take 2 quarts of Royal Purple, then the capacity only decreased by 3/4 pint, or 3/8 quart - not a huge amount.
Make sure you are on a level surface when you pour the oil in the fill hole. Fill until the oil level reaches the level of the stock hole. You can hold the stock cover up to the new cover to gauge more or less where it should be. Make sure you do not overfill because the oil may spill out from the breather tube and make a stinky mess everywhere. The operative words being "stinky" and "mess". If you feel that it is insufficient oil at first, drive your Jeep around the block once to let the oil settle and eliminate any possible air that may be trapped anywhere. Re-check the levels and add oil if necessary.
Wayoflife did a great write-up of the Solid differential covers install where he addresses the oil fill levels. Check it out:
http://project-jk.com/jeep-jk-write-...r-installation
Hope this helps and good luck.