Change differential fluid - 2002 Chevrolet TrailBlazer

First, I'm not a Mazda representative.
* Check warranty. Call dealer for service.

*** The following is for information only ***
* you need to access under the vehicle. There are two plugs (site and drain).
* Some differentials may only have the site plug. Draining may require the use of a pump or complete disassembly of back cover.
* Check the used fluid for metal flakes (use a magnet).
* Check the fluid for color and burnt smell.
* Removing back cover may be a preferred method if checking a car/truck for damage.
* Tips on changing differential fluid (dodge ram); https://www.youtube.com/watch?v=aSSYlMInjOQ
* Rear differential fluid change ; https://www.youtube.com/watch?v=lNLc3jmgq_Y
* Differential change (detailed); https://www.youtube.com/watch?v=KmqMUJb-E4M
* Topping off differential ; https://www.youtube.com/watch?v=afv4uhFwyz0
* Trans and differential change (Miata); https://www.youtube.com/watch?v=pfIPFfov9ns
* Differential fluid change (Mazda CRX-5); https://www.youtube.com/watch?v=T6kcC_7I1-8
* Changing front axle ; https://www.youtube.com/watch?v=jydxpsh13WQ
* Replace CV Drive 2001 Mazda; https://www.youtube.com/watch?v=vW_c6ZjyuLI
* Replace Mazda 626 axle ; https://www.youtube.com/watch?v=COvjd1iKnrI

Aloha, ukeboy57

Additional links; (some may void warranty. call support to check.)
* CV (Corvette) axle; https://www.youtube.com/watch?v=bH98nX8fb6M
* Changing axle (Ford) ; https://www.youtube.com/watch?v=HCVHPXmbOhA

How to Care for Your Car's Differential - Popular Mechanics

www.popularmechanics.com/cars/.../how-to-care-for-your-cars-differenti...

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Differential / Gear Oil Replacement - YourMechanic

www.yourmechanic.com > Auto Repair and Maintenance Services

How much does Differential/Gear Oil Replacement cost? Get an estimate instantly. ...Some vehicles have a front differential and others have a rear differential. ... I'm from out of town and didn't know who to contact to fix a truck I was borrowing.

How to Change Transmission Fluid & Filter ' Step by Step

www.transmissionrepaircostguide.com/change-transmission-fluid/

A do-it-yourself transmission fluid change is an affordable way to maintain and ... It is often recommended that you change the fluid in your car every 30,000 to .... lifted up my truck with a jack, Jack stands, blocked the rear tires and went at it just ...

How often gear oil should be changed - Testing Autos

Yes. Have the fluid changed before you blow the differential.

Action: Description

Inspect Cooling system hoses
Torque Body Fasteners
Inspect Idle speed
Inspect Exhaust system heat shields
Inspect Fuel lines
Inspect Emission System
Torque Frame Fasteners
Replace Air filter element
Inspect Drive Belt(s)
Change fluid Automatic transmission/transaxle
Inspect Parking brake
Inspect Ball joints
Drain, flush & refill Cooling system
Inspect Steering system
Inspect Brake system
Inspect Brake lines & hoses
Inspect Axle Shaft Oil Seal
Change fluid Rear differential
Inspect Driveshaft Universal Joint(s)
Inspect Constant Velocity Joint Boots
Change fluid Brake system
Replace Crankcase Oil Filter
Lubricate Door checks
Inspect fluid level Manual transmission/transaxle
Inspect fluid level Front differential
Inspect fluid level Transfer case
Inspect fluid level Rear differential
Change fluid Crankcase

HI, The transmission and differential assembly are two different devices that are linked by the drive shaft. Now; if your vehicle is front wheel drive only, you do not need to change your differential fluid because you wouldn't have one in that case. With that said; Changing the differential fluid will not affect your transmission. It will only provide better differential lubrication and functionality. Administering a flushing technique to both devices will only have an individual effect on both devices.

NOTE_ Differential maintenance is quite rare for the average city driver. Your transmission will require more attention than most differential assemblies. Now; if you do a lot of off-roading and pull heavy loads on the regular, i would have the differential assembly inspected every 16k. If not, simply, have the transmission checked every 10k for proper fluid and filter change.

your front wheel drive rx300 doesnt use gear oil, the differential is lubricated internally by transmission fluid. the trans fluid is only reccomended if its dirty. if its a dark brownish red thats normal. or if its pinkish red then its new. if its black or yellow then time to flush it out. if you decide to change the trans fluid I believe the spec is 3qts. check it with the engine running and cold. thats the most accurate way to check it.

if you have more than 75,000 miles than yes the fluid change will help.

also check for signs of differential fluid leaks. it may need a new gasket. the gasket should be replaced anytime you change the fluid.

I'm assuming that this is a 5 speed stick car because you mentioned 80-90 oil. This car has a transaxle, not a a separate transmission and differential. The transaxle houses the transmission gears and the differential all in one housing. There is a drain plug on the bottom a fill plug on the side. Here's a link to one of the best do-it-yourself 944 sites on the web. Click on the "garage shop manual" link in the sidebar and scroll down to "transaxle fluid change".

http://www.clarks-garage.com/

Loosen the lower bolts on the cover to drain the differential,remove all bolts,remove cover and clean cover, replace gasket or silicon, replace cover and tighten bolts to spec or snug + 1/4 turnrefill with proper fluid.

You have a transaxle, the diff is part of the transmission, drop the trans pan change the filter and refill with ATF+4 fluid.