Changed rear diff fluid on an '05
 

As most that have an '05 know, the drain plug on the rear differential is partially covered by the rear leaf spring.
I tried several methods to remove the plug, all yielding busted knuckles and a bunch of swearing.
Finally gave up and got out the old trusty air driven brake bleeder and sucked it out from the fill bung.
About 1.7 qts. came out, took right at 2 quarts to refill.
All the '05 folks out there save your sanity and just go in from the top.
Bill.

Sounds like you had a fun day!! :thumbs:

Not seeing the problem,


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And plenty of room to get in with the flex head socket wrench for the bottom drain bolt as well.
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Hence break it free with the socket wrench to state with, drop the socket off the wrench if needed, or just spin the bolt out the rest off the way.

As for draining so you don't end up with fluid all over the trans spring, easy enough to make a dam out of some plastic tube piece to flow the oil down and over the spring to the catch pan isntead.

Really, the hardest part of doing the fluid drain, is getting the car level on stands, so it will drain all the fluid out quickly to begin with, and then be level to fill it back up to the bottom of fill port isntead.

And no from the top, since I want the fluid to drain out the bottom, so it takes all the debris in the fluid out the bottom with it. Hence the reason that you change the fluid in the first place, is it packed with LSD clutch dust, and sucking the fluid from the top, is gong to end up with some of the old clutch dust fluid still left in the diff isntead.

Hence you do the fluid change, go hit the parking lot for some tight figure 8's to flush the LSD packs with new fluid (to flush away any dust still in them), and before you call it done, jack up one side of the back of the car at a time with it in gear/front tires chocked, and E brake off to do break away checks on the LSD packs via the axle nuts to make sure that the break away value is still at 100ft lbs per clutch pack side.

I changed mine on my 05, was not an issue. You can use a ball end allen wrench and socket for leverage . The plug isn't so tight that the ball end will break.

Getting to the fill plug with a ratchet was a piece of cake. I made sure I could get it broken loose first. It was the drain plug that was so tight that nothing would break it loose. It doesn’t help that the leaf spring covers a straight shot to it. The ‘06 and up guys don’t have to fool with this oversight by GM engineers.

my 05 auto car has never been difficult to drain or fill.

The 05 rear diff plug is a 'one year only' thing, they changed the plugs location after 05.