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How to Change Front Differentail Fluid

113K views 99 replies 42 participants last post by  Z15 
#1 Ā· (Edited by Moderator)
Hey guys recently did my diff oil in the front and i thought i would share with you guys how too.

Step 1
you need to get under your vehicle (either by stands, ramps, crawling under, or in my case on a lift we convinently have at the marina i work at!

Step 2
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If you have a Z71 package you can remove the front skid plate, it will make it alot less messy and easier!
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Step 3
Place a suitable drain container for approximately 3 quarts of gear oil

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step4
Remove the lower plug it is removed with a 13mm wrench or socket, its a long thread bolt in the bottom of the pick and has a plastic sealing washer on it. Once removed, remove the upper fill bolt which is removed with a 18 mm socket or wrench.

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Step 5
while oil is drainging i like to take a sample of oil to inspect and clean the metal shavings off magnetic bolt.
I noticed how dirty my oil was so i decided to flush my housing out with some fresh oil and letting that drain through (dont ask why im anal and i didnt like the color of oil!)
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Step 6
After all oil is drained i then cleaned bottom drain plug surface inspected drain washer (mine was still good)
and reinstalled lower drain bolt after drain bolt is installed then you can get your gear oil of choice i used a hand pump that attached to the quart bottles to fill the the differential and filled it with 75w90 yamaha gear oil that we use in boats (its the same gear oil as used in cars if not better it has extra anti foaming agents and is more resitance to water breaking the oil down, its also much sitckier and designed to cling to bearings and gears better)
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step 7

The differential will be full once the oil begins to flow out of the hole you are filling from. once oil is full clean o ring on top fill plug and make sure surface is clean and reinstall vent plug.

its a pretty easy thing to do that anyone can do

i hope this will help anyone that doesnt know
 

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#5 Ā·
I've been considering doing this, never been super auto-mechanically inclined so I have been cautious. This looks really easy though...

Chevy dealer said I need to replace my front and rear diff fluids at $85 an axle. I think I'd rather do it myself, save a little money, and put in a quality lubricant like AMSOIL.
 
#11 Ā·
One rule of thumb that I like for tasks like this (drain and fill plugs) is to always remove the Fill plug first. This way you know you can re-fill it once it drains! Otherwise you risk ending up with an empty diff (or transmission, etc) when you strip the fill plug, don't have the right tool on hand, etc.
 
#13 Ā·
ASTE25 said:
It's really easy. The hardest part will probably be cleaning everything up for the new gasket.
Agreed. I was lucky to be able to use the base auto hobby shop and their air powered gasket wheel. Without it, I would've spent a lot of time and elbow grease getting the remains of the old gasket off.

Also, I thought it was worth it to give the diffy cover a coat of engine enamel.
 
#14 Ā·
Luckily I believe 07.5 and up nnbs use a metal gasket with rubber seal on it and they don't leave really any material behind on the rear. And for removing the fill plug first That's not a bad idea I'm just use to removing the bottom first on boats lol. So it don't pour oil on ya. And on a boat you fill from the bottom up to remove trapped air.Our diffs are vented so that technique wouldn't matter for this hahah. I have never seen a Fill plug strip one a dif but that definily seems like a good idea to check first !
 
#15 Ā·
Good write up. I've been trying to change the fluids in my 4wd boxes for the last week. If I had the tools available now as I did when I worked at Valvoline, I would have it done in 15 min. Just running back and forth to town.... Going to try to find a syring to refill my empty front diff.

I have a chrome rear diff cover that I'm going to be installing, if all goes well, I may post it.
 
#19 Ā·
so i like this write up but i see where you all are talking about gaskets ..when u mention them that is talking about the rear differential correct? sorry if that is a stupid question but i didnt think the front diff had the gasket like the rear.
 
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