Hey guys, Just picked up a J30 diff. How do I "flush" the diff out and how much do I fill 'er up to? This is my first time doing this... ever. No seriously... it is...

LOL Thanks for any help!

 

There is a drain plug on the bottom of the differential cover. Open that plug with the differential over a drain pan. Allow all the fluid to drain. Reinstall the drain plug.

There is a fill plug higher up on the diff cover. Remove the plug. Place the diff on a level surface and pour the 80W-90 fluid of your choice into this hole. The fluid does not need to be specifically for limited slip differentials, since the VLSD is a sealed unit. Fill the diff until the fluid level is even with the fill hole. This is why it is important for the diff to be on a level surface. Once full, reinstall the fill plug and you're done! Simple!

 

Nice write up! THANKS!

I should be getting this diff in my car this weekend if all goes well.

 

No Problem! Let us know how it turns out...

 

Hopefully I'll have this done and installed in my 14 by Saturday afternoon. loading it up and headed to my cousin's shop in the morning to use a lift!

 

a picture of the drain (bottom) and fill (top left) plugs

 

Thanks Bumnah, I've never done a diff fluid change before (never kept a car long enough LOL) But yeah, this helps out a lot!

 

when i bought my j30 diff i flushed it with 5-30 weight oil at the shop i just pumped in oil till it came out clear took like 12 quarts lol. i drained it put the drain plug back on.

i filled my diff on the car but thats cause i had a lift anyway just put 80-90 gear oil in the fill plug untill a little leaks out from the fill plug then it has enough mine took like 1.5 quarts.

when my SR goes back in im using Royal Purple 75-90 gear oil in my tranny and diff so ill tell you how it feels... i hope it actually is better not just snake oil cause it was $10 a damn quart lol

 

pickup a cheap pump from harbor freight. makes life a lot easier I ran a long pipe and slowly drained fluid into the diff when i first did it. what a ****ty experience that was. i bought a $5 harbor freight pump made the job 50 times easier and faster.

 

AZ has a proper pump for around $6 and is proper to do the job has fitments for the bottle of fluid so u don't even have to use any adpator.
I just chenged on my car yesterday.