differential

[HeWhoKillz]

I have an 85 300zx which is rear wheel drive. I am new to the entire set up. With the differential, can someone explain to me how it is maintained? Is the fluid ever changed so often or flushed or anything like that? Is this something one can do themselves or do you have to take it somewhere? I want to know as much as I can.

[shorod]

The rear differential does use a gear oil and that oil needs to be changed at some interval. The owner's manual/maintenance manual would be a good source to determine what the appropriate interval is and what viscosity of fluid to use. If the car has a limited slip differential there will likely be an additive for that that needs to be added.

Your Nissan may very well have a drain plug for the rear differential. If not, you would need to unbolt the gear cover at the rear of the differential to drain the fluid, then reseal and reinstall the cover. There will be a fill plug on one of the sides. These fill plugs often are sized to fit a standard 1/2" or 3/8" drive ratchet head (square drive).

A good tip that I learned on this forum is to make sure you can get the fill plug loose before you drain the fluid.

-Rod

[HeWhoKillz]

Originally Posted by shorod

The rear differential does use a gear oil and that oil needs to be changed at some interval. The owner's manual/maintenance manual would be a good source to determine what the appropriate interval is and what viscosity of fluid to use. If the car has a limited slip differential there will likely be an additive for that that needs to be added.

Your Nissan may very well have a drain plug for the rear differential. If not, you would need to unbolt the gear cover at the rear of the differential to drain the fluid, then reseal and reinstall the cover. There will be a fill plug on one of the sides. These fill plugs often are sized to fit a standard 1/2" or 3/8" drive ratchet head (square drive).

A good tip that I learned on this forum is to make sure you can get the fill plug loose before you drain the fluid.

-Rod

Possibly a silly question but how do you get the fluid into it if your working from below? If it was in the engine bay like the engine or transmission fluid it would be somewhat easy.

[vgames33]

There are two plugs, both take a 1/2" square drive (ratchet extension). Make sure you tap the extension in with a hammer before trying to remove the plug or you may strip it, and make sure the fill comes loose before you drain it.

Harbor Freight sells fluid pumps that work well for filling diffs. One is a giant syringe, the other is a hand pump that fits in the oil bottle. Its a messy job either way, so wear gloves. Fill the differential until fluid drips from the fill plug.


This page has capacities and fluid type for your car. You have a 3.54:1 open differential in the 85 Turbo.
http://www.az-zbum.com/information.differential.shtml