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Over filled front Diff

960 Views 7 Replies 5 Participants Last post by  MTDIRK
So a buddy helped me install a new Riddler diff cover on the front and just filled to the fill hole. It took 3 qts. I didn't bother to do my research on here first as in the past the fill hole had been a good amount. Afterwards I thought 3 qts seemed like a lot and began searching on here and found Dr D recommend fill to bottom of axles and a mix of opinions about whether its ok to over fill or not. I have a couple questions:
1. Do I need to bother disassembling and doing another gasket or can I just let it leak out? Is this going to cause any real damage?
2. How do I measure to figure out where the bottom of the axle is to get the correct level?
3. Does anyone else who has the Riddler diff covers know how much you normally put in?
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Read the tag on the OEM diff cover. It probably states somewhere around 44 oz. You have 96 oz in it if you used all 3 qts. Rubi's have a drain plug on the lower side. I would not put in more than 48-50 you need to drain about 48 oz.

If you don't, here's what will happen:
1. The excess gear oil will come out of the air breather line by the radiator. It will make a huge mess in the engine bay.
2. The excess gear oil could cause one of the diff seals on either side of the pumpkin to blow out. This requires pulling out the locker to get to the seals.

It helps to read the FAQ &/or owner's manual before doing a job like that.
Good rule of thumb is to fill to about the line that's 1/2 way up the axle tubes. A bent up metal coat hanger can be a pretty good dip stick ... The amount of fluid will vary depending on your diff cover but 3qts sounds like a lot.
But then the other key thing is "does the diff cover you are using allow for more fluid when filled to the proper level".

The dip stick method above is the ticket to getting it close to proper level.

I do believe that from past threads I have read, is that an overfilled front diff will start puking oil out, from the breather tube I think.
Yea I should have reread the FAQs but that doesn't specify how much extra fluid goes in for larger diff covers. I usually use the fill hole as the rule of thumb but the larger diff cover and much higher fill hole means my rule of thumb no longer applies.

I guess the best way to figure out the new correct level will be to make a dipstick while the cover is off. I think 45-50 oz should be sufficient.
Oh and I decided to just redo it. Better safe than sorry and that way I can measure exactly how much I put in just in case I need to adjust the amount next time.
I checked mine cause it seemed a little low, so I added a bit of fluid, and it was fine until i took it off camber then It began puking out the sides, its at the correct level now. :lildevil:
Decided to do the transmission while I was at it, but can't get more than 1 qt in there. I tried jacking rear up as high as I could in the garage with no luck. I will pull it out into driveway tomorrow to finish filling. Couldn't find anything with the search function but how high should the rear be lifted to get the full 2 qts in?
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