DIY: Filling Rear Diff , Trans Fluid using Air Compressor

[cn90]

Hi guys,

Whenever you fill the Rear Diff or Trans, it is always awkward under the car with spilled fluid etc.

Some of the solutions are:

1. Squeeze bottle ---> slow and incomplete emptying.

2. Fill by suction gun ($10 at Harbor Freight) ---> messy.

3. Fill by gravity. The only problem is you need 4-5 ft of tubing, but it is a minor issue.
Please see photo of my tip below...

4. Fill using compressed air. I just tried this today and the best thing is: it costs you less than $1 for the tubing if you already own an air compressor!

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* Fill by gravity: Please see 1st photo.



* So, I have some time today, if you already have an air compressor, these are what you need:

1. An empty bottle, I like the "Simply Lemonade" bc the bottle is sturdy, the cap is solid plastic, and it is FREE (I already drank all the lemonade lol...).
Of course you wash the bottle and cap and let it sit overnight in your kitchen so it dries properly. Absolutely do not allow any trace of water in the
bottle. Any doubt, use small amount of gasoline to clean the bottle and hose and let it evaporate first...

2. Clear hose is cheap at local hardware store, about 30-40 cents/foot.
One hose is short and enters the cap for only 1": this is for compressed air.
The other hose needs to go to the bottom of the bottle: in the illustration, this hose is not long enough in the photo bc this is all I have in my garage
for the test. You will need about 2-3 feet so it can go into the rear diff.

3. I have a 60 mL syringe lying around.
- With syringe: water shoots out about 10 inches.
- With compressed air at 5-7 psi, water shoots out at 5-6 feet!
So, turn your air compressor on for only 5 sec. stop and measure the pressure, if it is < 10 psi, it is OK. I honestly do NOT know the pressure at which
the bottle starts to bulge: can someone test and test the rest the burst pressure?

Of course 75W90 fluid is thicker than water, so it will take more time to pump 75W90 into the rear diff. I have not tried the 75W90 fluid yet. So far it
is only testing with water.

Good Luck and hope you guys find this useful...