How do I change diff fluid when...

[KDMatt]

...this thing is in my way. Yes it's a metal bar and it covers up the fill plug, how do I get to it? As you can see, my diff is need of a little TLC, so this is something I want to get figured out ASAP. Thanks!

[westpak]

I used something like this http://www.partsamerica.com/ProductDetail.aspx?MfrCode=PBI&MfrPartNumber=648960&CategoryCode=3487

I got one at Napa

[AZ-240z]

...this thing is in my way. Yes it's a metal bar and it covers up the fill plug, how do I get to it? As you can see, my diff is need of a little TLC, so this is something I want to get figured out ASAP. Thanks!

Do a search on "changing differential oil" and you will find out what others have done. Hope this helps.

Dan

[John Coffey]

One tip:

Remove the fill plug first before removing the drain plug. Reversing the order can leave you high and dry if you can't get the fill plug out.

[wal280z]

I used about 3' of clear 3/8" dia tubing. Removed the rubber plug in the bottom of the spare tire well. Attach tubing to new fluid bottle and insert other end into fill hole. Keep an eye on the fluid. (if you attach the tubing to a funnel the fill goes much quicker)

[KDMatt]

Hey guys, thanks for the help so far. My question isn't about how to get new oil in there, it's about how I'm supposed to thread the fill-plug OUT. This bar won't let me turn it out far enough to remove it!

[westpak]

ah can't help there mine came out fine

[geezer]

You could use the same method used on a marine engine outdrive, if you had to. Do what John said, make sure the top plug can be loosened. You do not have to remove it completely, just enough to leak out when full. Use a pump (available for about $15.00, or borrow one) and fill from the drain hole until it leaks out the top hole. Tighten the top plug then quickly tighten the lower plug.

[sblake01]

If you fill it from the drain hole, how do you intend to stop it from leaking out of the drain hole while you're filling it?

[m4xwellmurd3r]

Speed and dexterity probably haha.

speaking of changing diff fluid, I need to change the oil in my transmission.I haven't really found any good info, but I know i can drain it from the bottom, and if I take out my center console there's an access plate of some sort on top?

[geezer]

Anyone who maintains their own boats knows the drill. On a boat the upper plug is removed to allow air to escape and give you notice the outdrive is full. The plugs are smaller on my Mercruisers but I wouldn't be above trying this on my Z which has a similar situation. After using the pump to fill (the pump is sealing the lower opening at this point) you will see the gear oil running out of the upper hole. Replace the upper plug first, then quickly replace the pump with the lower plug. I perform this ritual every time my boat comes out of the water.

[WarrenZ]

The drain plug on the diff has a tapered thread so if it is over tightened it is very difficult to get out. Under normal circumstances you should be able to undo it without dismantling the rear suspension as long as you square bar fits into the drain plug hole perfectly.

If you can get the car off the ground a bit or on a hoist then you can use a longer bar and the extra leverage may do it otherwise you will have to remove the bar across the diff to give yourself more room to operate.

I had the exact same problem just after I bought my car many years ago, ended up takingthe car to a workshop that specialised in Z's and paid them to change the oil. They had to remove the bar across the diff and then butcher the plug to get it out and then they fitted a new one with correct tensioning. A bit more expensive than I expected but I was watching and they almost an hour to get it out, so money well spent.

Warren