Transfer Case and Rear Differential Fluid

[BikerJohn]

I'm looking to replace my gear oil in the Transfer Case and Rear Differential.

Just wondering if anyone has done so?

Called my local Nissan and they told me to use Gear Oil rated either 75/85 or 85/95 weight and sells for $15/L. I'll need about 1.5L to do both.

My '03 AWD has about 90,000 miles(144,000 km) and I do pull a trailer on a regular basis so I thought that it wouldn't hurt to do the change while the weather is decent.

Cheers,
John.

[ekaxel]

rear diff is really easy. Xfer case is tough due to limited access to the
filler plug.. I replaced with Amsoil synthetic. Don't forget the front diff! DON'T EVEN CONSIDER USING THE DEALER'S OVERPRICED STUFF!

[BikerJohn]

Thanks for that ekaxel. What weight oil did you end up using? Did you also replace the crush washer too or did you use a type of liquid gasket?

[ekaxel]

I believe it was 75W90. I don't remember a washer on those drain plugs....
Sorry, it was 4 years ago!

[Eric L.]

Try as I might, I could not access the transfer case filler plug, so I let the dealer do it. It wasn't unreasonable, something like $150 for both transfer case *and* rear diff after I used a coupon.

[ekaxel]

With the right tools.........

[Eric L.]

Originally posted by ekaxel
With the right tools.........

I had a long box wrench, and got it over the fill bolt. Even had enough length to hit the end with a rubber mallet - it wouldn't budge - it was on there very tight.

[BikerJohn]

Well; I did the fluid change on my Rear Differential and my Transfercase.

The job took about 1/2 hour for the rear and about 1 hour for the Transfercase. The only reason it took that long for the Transfercase is that the filler plug is Very hard to get at.

I used Castrol's Syntec 75W-90 Synthetic Gear Oil($12.50/946mL) and needed only 1 bottle for both.

The Rear Diff took about 500 to 520 mL of oil and the Transfercase about 300 to 320 mL of oil.

Tool/Parts you need:
A- Drain Pan
B- Rags or Paper Towels
C- Gear Oil
D- 2 Aluminum Crush washer for the Rear Diff Plugs
E- Liquid Gasket for Transfer Case Plugs
F- 10 mm Allen Key-type wrench for the Rear Dill Plugs and for
the Drain Plug on the Transfer Case
G- 12 mm Boxed end wrench for the Filler Plug on the
Transfercase. You should have 2(an 8" or so long one to
loosen + a short one about 5" or less to work after loosening)
H- Liquid Wrench or some other penetrating oil
I- 1/4" Inside Diameter Tubing about 12" long(To pump the oil in)
J- Cardboard (it gets messy)

How To:

1)-Park on level ground. I used 2 2x4's stacked so the whole car sat up an extra 3" off the ground for clearance.

2)-Spray some Liquid Wrench on Filler and Drain Plugs and let sit for a few minutes to soak.

3)-IMPORTANT....Remove the Filler Plug FIRST*. If you cant undo the filler plug; STOP and have it done in a shop. No need to go any further if you can't fill
There may be some oil that comes out of the Filler Plug so have your drain pan under it.

4)-Remove Drain Plug and let oil completely drain. The drain plug on the Rear Dill has a built in Magnet. Wipe it clean. After the oil is drained; install the new crush washer and install the drain plug.

5)-Attach the 1/4" Tubing to the Oil bottle. Insert the Tubing into the Filler hole. Squeeze the Oil bottle and fill until the oil over-flows out of the filler hole.

6)-Install new crush washer on filler plug and tighten. Wipe area clean or use degreaser afterwards.

The proceedure is the same for both Rear Diff and Transfer Case with the execption of the crush washer on the Rear Dill and Liquid Gasket for the Transfer Case.

Be carefull about dripping oil onto the exhaust pipe when doing the Transfer Case. Stuff rags or paper towels up in the "drip zone".

Here are some photos.

[BikerJohn]

Photo of the Rear Differential with plugs out. Oil saturation around the holes are from spraying the Liquid Wrench and not from a leak.

[BikerJohn]

Shot of the Drail Plug. It has a long magnet built into the tip of the plug that should be wiped clean before re-installing. Also you can see the old aluminum crush washer.
The plugs are removed using a 10 mm allen wrench with an extension pipe for leverage.

[BikerJohn]

Here's the filler plug also with a crush washer.

[BikerJohn]

Here's a shot of the 1/4" tubing used to fill/squeeze oil into the filler hole.

[BikerJohn]

A photo of the Gear Oil. The Old oil is on the Right compared to the new oil on the Left.

[BikerJohn]

I didn't get a chance to photograph the work on the Transfer Case.

The filler plug is up and just behind some structual member and very tight to get to.

The only tool you can use (I had) was a 12mm boxed end wrench to get in. I used a longer one first to loosen it and then I had to use a shorty 12mm boxed end(about 3 to 4" long) to get it in there and work it the rest of the way off.

Once that filler plug was off; it was easy like the rear diff.
Those plugs where fitted with liquid gasket(grey).

I hope this will help others do the job too if they would like to get a little personal with their MO

[njjoe]

BikerJohn-

Nice job!

I made this thread a "sticky" so it will always appear near (or at) the top of the maintenence section so others can easily reference it.

Thanks again!

-njjoe