Diff Fluid Change - Warm or Cold?
Thread Starter
Burning Brakes
Joined: Jan 2001
Posts: 1,215
Likes: 441
From: Loir Valley Sarthe, France
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2024 C3 of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
Diff Fluid Change - Warm or Cold?
After a diff re-build I'm now ready to do the first change of fluid after the "break-in" period. So, should that be when the fluid is warm (and all the possible "sludge" is stirred up) or is it best to do it when the diff is cold and the fluid has settled ?
Thanks!
Thanks!
Melting Slicks
Joined: Oct 2011
Posts: 3,453
Likes: 67
From: Midland Ontario
NCM Sinkhole Donor
Was a drain plug installed as part of your rebuild? Mine was sucked out by a long tube/syringe at an oil change place so I could get easy access.....so mine would have been warm.
Thread Starter
Burning Brakes
Joined: Jan 2001
Posts: 1,215
Likes: 441
From: Loir Valley Sarthe, France
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2024 C3 of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
Thanks guys! Warm it is then. And no, no drain plug (After the unfortunate way the re-build costs escalated into the ionosphere extra work like that wasn't an option!), so I'll be using the trusty pump.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Don't install a drain plug unless you have the diffy disassembled and can assure getting ALL metal chips and filings out of it. Not worth the risk for an assembled 'punkin'.
You can fill the case with room temp lube and posi fluid, until it just starts to run out the fill hole. They didn't warm the lube when they installed it at the factory.
You can fill the case with room temp lube and posi fluid, until it just starts to run out the fill hole. They didn't warm the lube when they installed it at the factory.
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Don't install a drain plug unless you have the diffy disassembled and can assure getting ALL metal chips and filings out of it. Not worth the risk for an assembled 'punkin'.
You can fill the case with room temp lube and posi fluid, until it just starts to run out the fill hole. They didn't warm the lube when they installed it at the factory.
You can fill the case with room temp lube and posi fluid, until it just starts to run out the fill hole. They didn't warm the lube when they installed it at the factory.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
You CANNOT assure getting ALL shavings and chips out of the case by simply draining that thick gear lube. If you flush it out WELL with a solvent like mineral spirits after drilling/tapping, you MIGHT get them all. But, it only takes one cutting to get into a bearing and waste it.
There are lots of repair shops doing all kinds of questionable things. Just because some repair shop does it that way doesn't mean that's the right way to do it. But, it's your hardware....
There are lots of repair shops doing all kinds of questionable things. Just because some repair shop does it that way doesn't mean that's the right way to do it. But, it's your hardware....
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