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Sorry, not the motor oil, I use Mobil 1 every 5000 miles. I was asking about transmission, rear axle, radiator and fluids for clutch and brakes.
No worries! It's just that you left yourself wide open for that one!! Plus, Helga is like Tom Brady at the goal line-If he gets half a chance, he's gonna score!!!!
Seriously though, I didn't change my A4 fluid and filter until the 100,000 mile mark. Can't comment on the 6 speed. As for the diff, I changed that at 100,000 miles, too. Here's ammo for Helga-I've still never changed brake fluid or the fuel filter!!! But it stops fine, and goes even better!!! Right now.... This minute....... Anyway, I've changed the coolant every 4 or 5 years, no matter what the mileage on it is. Never more than 5 years. I also use distilled water, mixed at a 45% antifreeze, 55% DW. I've changed the R-134A 5 or 6 times . Slow leak.....
Last edited by grinder11; Apr 16, 2022 at 03:53 PM.
Motor oil, when it gets dirty around the 6~8K mark, or yearly, which every comes first.
Brake fluid should be power flushed every two years, including using a Tech II to power cycle the abs pump to get the old fluid out of it as well.
Clutch fluid, start with ranger way to get it clean (about three times in three weeks), then just replace the fluid in the reservoir around every 3 months to keep the fluid clean.
Power steering fluid, about every 6 years, or sooner if road coursing and the fluid starts to look burnt sooner instead.
Trans and diff, just normal street driving, 100K is fine, but if auto-crossing, then more like 50K. If dedicated road course car, replace it when it starts to become dirty or burnt instead (could be a couple times a season or more).
Note on diff fluid, and really just want to take a look of the color of it (open the fill plug and stick your finger in the fluid and wipe it on a white paper towel). The Diff has two sets of LSD clutch packs, and their wear is the reason that fluid turns black. So first check is to get one tire up in the air at a time to put a torque wrench on the axle nut to confirm that the clutch pack per side still have a break away value of 100ftlbs and it not time to pull the diff apart to replace the clutch packs due to wear. A dedicated road course cars can eat through the diff clutch packs in under 20K, while just street driven cars, clutch packs can last 100k or more instead. So your either replacing the fluid due to the amount of clutch dust wear in the fluid, or just changing the fluid out due to humidity/water collecting in it, so the water does not rust pit the bearings isntead.
As for lube for the Diff, use only this,
Hence some other after market lubes are too thick and do not allow the clutch packs to flush out correctly which cause them to chatter, while some other after market lubes are too slick, and can lower the break away values of the clutch pads still in good condition isntead (read peg leg burn outs since the break away values of the clutch packs are too low)..
On the C6 trans, stay with the fluid type FA , since that fluid is the best to prolong the life of the trans syncro's.
And the last one, windshield wiper fluid, since no one uses it to keep the car clean longer between washings. So no, you don't need to change it, but you do need to add some more methanal to it, to keep its freezing temps up if you live anywhere where the temp does drop below freezing. So when doing fluid flushes like the brake fluid every two years, best to just add a Yellow bottle of HEET to the wind sheild wiper tank to bring the fluids anti freezing level back up.
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Right now.... This minute....... Anyway, I've changed the coolant every 4 or 5 years, no matter what the mileage on it is. Never more than 5 years. I also use distilled water, mixed at a 45% antifreeze, 55% DW. I've changed the R-134A 5 or 6 times 
. Slow leak.....
