The car only has 20K miles on it. Car has received oil changes, new tires recently since the old set was the original tires. My question is, should I change ALL the fluids like rear end, transmission(6 speed) Belt, Fuel Filter, all other filters? The miles are low, BUT the car is 20 years old now....

 

If it was my car, I would.

 

it may have low miles....but every seal....gasket....rubber ....has aged....expect leaks

 

yes i would , valve cover gaskets might be on the list too.

 

I definitely would replace all the fluids and filters. Puts the maintenance list in your hands with no wondering if it was done.
Wait until you see that power steering fluid. It gets dark real quick in these cars, even w/ low miles.

 

If it were mine, this would be my thought process:

- Manual trans. Age isn't much of a factor in terms of fluid life here. 20k miles doesn't require a change unless the fluid has been contaminated (such as by failed internal parts). Auto transmissions are different as they typically see more heat and fluid contamination (due to natural wear of friction materials), but even an auto wouldn't be "due" for a change at this mileage (though I would probably do a pan drop and fluid/filter change if it were mine and an auto).

- Rear diff. An '02 would have a Torsen LSD, which doesn't use the cone style clutch of the earlier Auburn LSDs. For a Torsen, I also wouldn't worry about a fluid change at 20k miles. If it were an earlier Auburn (or if the car was an SS or Firehawk optioned with the SLP Auburn upgrade) then I would change the fluid (especially since most folks ignored the factory recommendation to do a fluid change at 7,500 miles with this rear). Either way, I'd open the fill plug at the top of the diff and just make sure that the fluid level is full (should be at or very near the bottom of the fill plug).

The brake fluid has certainly aged and is subject to moisture contamination, so I would change that. Power steering fluid should be checked for coolant contamination (as the factory power steering cooler is known to fail and cross-contaminate these two fluids). Either way, this fluid is subject to a lot of heat (as the factory PS cooler is poor at best), so I would change it as recommended above. I would also consider deleting the factory PS cooler, but that topic is covered in great detail in the FAQ sticky in this section. Coolant should be flushed no matter what at this age. Belts and various filters could probably use a change.

FWIW, my '98 has 19k miles so I'm pretty much in the same place as your car. The only "leak" I have is some weeping of the rear pinion seal, but it hasn't changed much in the last ~15 years so I've just left it. Very common problem on these cars regardless of mileage. Beyond that, I haven't needed to change any gaskets or seals, and nothing else leaks. So I wouldn't worry too much about that. Contrary to some of the internet lore, these cars don't fall apart from limited use and low mileage as long as they are not completely neglected. Mine has rarely seen more than one tank of gas per year for the last decade, and about 2-3 tanks per year before that, and it's still doing great.

 

^^^^ I'm +1 on this,, I've run a few Torsens, they seem to be ok with a lot of neglect but they definitely seem to work better with a good clean oil in them. (But I use mine off-road.. )
I thinks a function of the type of pressure your putting on it, especially high torque LOW rpm, I've spalled the surfaces on 2 of them rock crawling...
The Detroit version NEEDS to be changed. its a very high scrub unit and gets hot..

 

^^^^ One more nod to RPM above. I'd leave the manual trans and rear diff fluids alone.

I agree on the coolant also, but with this observation: Take off the radiator cap and shine a light into the filler neck. If it is cloudy or there is any sludge, the Dexcool has gone way bad and a good flush is mandatory. That being said, on both the G8's we have owned, the coolant has been crystal clear and like new at 10+ years.

 

I would recommend a straight 140W-GL4 conventional oil in the rearend, I too have a Zexel Torson LSD unit in Sara (2001 Z28)

 

Factory recommendation for the Torsen LSD is 75w90 synthetic. I don't see any reason to deviate so significantly from that recommendation for normal street usage, though other (racing, high heat/excessive load, etc.) applications may vary.

 

It probably doesn't need all the fluids changed, but some of them are fairly cheap and easy to do, so then you have the peace of mind of knowing that it has been done and what is in there. Stick with the recommended synthetic 75w90 in the rear end, just need a couple of quarts, a cheap hand pump that might even come with the fluid, and a gasket, then you know that it has been done and that the level is correct. I would not worry about the transmission fluid, manual or auto, until you get to the recommended service.

I definitely would change out the brake fluid, it likes to attract water (the term is hygroscopic) and the system does not circulate the fluid, what is working in the business end (brake cylinders) just stays there. I would want new brake fluid. Get a hand pump like a Mityvac and it is easy to do by yourself without someone else pumping the brakes.

Power steering fluid. Just look at it, gets dirty and brown over use, yours is likely still pretty clean. If you want to use a turkey baster to pull some out and add new, go right ahead. Doesn't need it though.

Hoses are probably fine but the belts will be old and I would change both belts, not a big deal, and again, then you know that they are new. Gas filter is another easy "peace of mind" thing to change, but I would run a few tanks of gas through it with some good gas treatment like Techron (please no Seafoam) and then change the fuel filter.

You essentially have a new car, that has sat for a long time. It needs to be driven, and then you monitor things, drive it some more.