ek1

I have a 2002 Firehawk. The diff oil has been changed 5 years ago. The car has been barely driven (only around 600 miles) since then, but I want to change the fluid due to age. The diff cover is NOT leaking.

This is one of my "forever" cars and is in a near-new condition. I do not have access to a lift or to a good mechanic I can trust.

The question is: can I use a automotive fluid extractor pump (like this one on Amazon https://a.co/d/05cuVDHc) to suck the fluid out through the fill plug and then refill the diff with new fluid? I realize that some of the old fluid will remain in the diff, but I am going to try to get the tube to the bottom of the diff, so most of the fluid will come out.

Biebs

Yes you can. I’m guessing the fluid will come out very clean. Compare the old fluid to fresh fluid.

depending on your environment and storage. A little obsessive to change 600 mile diff fluid.

Finkledbody

Interesting what information is becoming available to us. One thing interesting is how older fluids lose their anti-frothing agents overtime. Aerated oil doesn’t lubricant well so time alone warrants fluid change. Plenty of videos depicting this phenomenon that we enthusiast should be privy to.

change ur fluids often folks. It could save u a headache later.

RPM WS6

iTrader: (3)

I agree; 5 years/600 miles does not warrant a diff fluid change unless those 600 miles were done a quarter mile at a time. Age alone is not such a factor for lube that is not exposed to combustion byproducts (unlike engine oil), and especially if the car is stored indoors.

As this is a Firehawk, it might have been optioned with the Auburn diff (this is just something to be aware of regarding lube selection). If not, the standard factory recommendation of 75w90 synthetic is fine for the Torsen LSD.

Finkledbody

Combustion gases is not what breaks down anti-frothing agents. Time allows the anti-frothing agents to absorb into the oil. Once that happens the oil will aerate and you lose lubrication.

This can be tested by anyone but Check out The Motor Oil Geek on YouTube. He does a simple test where he takes brand new motor oil that has been sitting in a shop for 10-20 years. He uses a frothier on the old oil and shows how the bubbles don’t go away. The oil is fresh by every measure but the anti-frothing agents no longer work. Bubbles are the death of metal components as it’ll introduce heat and premature wear.

Gear lube will also have anti-frothing agents that will too absorb over time. How much time is the question. A simple test could determine if the fluid is still good.

Y2K_Frenzy

Yeah. Suck that stuff out. Do it twice maybe if you want to.

Treburkulosis

I like redline. I ran it in my Ram and I am running it in my Z. I just took mine to a local shop I trust and they did it for me.

RPM WS6

iTrader: (3)

I wasn't referring to anti-frothing; just that engine oil which has been "used" (even if only a small amount) will contain combustion byproducts which can prove harmful to internal components over long periods (such as sitting for many years). This is not an issue for gear lube, as no combustion should be taking place in the differential.

I would absolutely not worry about 5 year old/600 mile gear lube in a non-racing application, unless maybe the car had been stored in a terrarium. Personal experience with many old, RWD cars tells me this is not going to be a problem, but obviously it's up to the owner to do whatever he feels is best.

JohnnyBs98WS6Rag

iTrader: (1)

In all the (20+) cars I've owned over the years, I've never seen any manufacturer recommend differential fluid changes based on time and not mileage. I can't imagine a heavy, sticky lube like gear oil would not leave a protective film on the metal parts that would magically disappear and leave both metal surfaces bare to grind against each other when an air bubble was encountered. Sorry, not happening.

Finkledbody

premature bearing failure happens all the time in 10 bolts, maybe there is a coincidence?

Perhaps we should learn more here

Y2K_Frenzy

When I first got my ‘00 Z28 two years ago I sucked out what I’m assuming was the original fluid through the fill hole and it had 27k miles on it at that time. The fluid that came out was almost a lime green color. It looked pretty bad so I did two suck and fills. The pinion seal was leaking at that time so I bet the green tint came from moisture getting in. Later down the line I took the cover off and all was well inside. If not for the leaky seal I bet the oil still would’ve been good.

Y2K_Frenzy

Maybe people are driving their Fbods hard and the 10 bolt isn’t very robust? Could that have something to do with it?

Y2K_Frenzy

Construction equipment manufactures list their service intervals in time (hours) and not miles.

Y2K_Frenzy

At little off topic but it’s along the same vein. About 6 months ago I changed the transfer case fluid in my truck (ATF) and I was surprised at how dark that it was based on its little usage. It’s a 5 year old truck and it had around 70k miles on it at the time. I can’t really say how many miles that it was driven in 4wd but I bet it’s proably something like fifty on the high end. The fluid that came out pretty much looked the same as the old 70k mile ATF that came out of the trans when I changed it. I guess the transfer case gets hot even when it’s not in use. Not hot to the point of combustion but hot enough to give the ATF in it that old ATF look.

wannafbody

iTrader: (2)

I changed my factory fill diff fluid at 22 years and 110,000 miles.

RPM WS6

iTrader: (3)