Diff fluid lost on front axle rebuild?

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Jan 25, 2008
Opelika, AL
I'm about to have my front axle rebuild done tomorrow and I've bought everything I need except the Diff fluid. I have 2 quarts but I don't have lockers and need 3 to fill it all the way up. So my question is Will all of it leak out or just some?

I would go ahead and get the diff fluid but I've been using Amsoil and the local dealer has been bought out recently.
well, given that the diff bottom half is lower than the tubes, there's got to be some oil left in there unless the truck is tilted. Then again, it's probably full of grease if you need the seals replaced and who knows what junk will end up in it during the axle job. So buy 3 qts of cheap diff oil, run it for a while and when things settle down, put in the good stuff.
Good advice. You covered some of the things I had in mind but didn't put in my thread like the possiblilty of something getting into the diff. I'll get some more diff fluid and save the Amsoil until later.
Don't most people pull the fill and then drain plugs on the front diff and drain out all of the diff fluid anyway :confused:

I assume you were not planning to do this? But, you could have pulled the plugs and captured the diff fluid for reuse...

Regardless the above suggestion to run some cheapy fluid and then drain and fill with good stuff is an excellent suggestion and much better than trying to reuse what you had. Was the "old" fluid almost brand new??
Ditto on E's suggestion - drain and put some cheap fluid in the front diff for a couple weeks before refilling with Amsoil.

I assume you were not planning to do this?

Was the "old" fluid almost brand new??

You're right, I wasn't doing it myself. I'm traveling about 100 miles so I wanted to make sure I was fully prepared. The old fluid has about 4k miles on it or less. I bought some different fluid since the last post and am ready to go.
I didn't change my diff fluid when I did my front end. It had just been replaced. My seals were good and what very little diff fluid that did drain out looked very clean. If you clean everything up prior to rebuilding the front end you shouldn't absolutely need to change the diff fluid, but the advice you've been given about running some cheap stuff for a couple thousand miles until you can source your good Amsoil is the best advice I've ever seen on multiple threads on this board discussing this subject.
80/90 gear lube in the 5 gallon bucket from the local parts store. Change every 2 years. Both diffs & the Tcase.


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