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Differential fluid change without using an OBD11 to check temp first?

enobiko

Ready to race!
Location
NE Ohio
Car(s)
2017 SE 6 MT
It may take another week for me to get access to an OB11, and I want to change my differential fluid, while I'm doing all 4 brakes. I'm supposed to have the differential fluid to between 20 degrees and 40 degrees Celsius before I start, do I have to wait until I can measure that accurately with the OBD11, or can I just drive it around for xx minutes. The outside temp will be 40-55 degrees.
I suppose I could wait until after Easter, but the weather is always uncertain that far in the future. We've had crazy weather recently, hard to know what's going to happen from one hour to the next!
 

enobiko

Ready to race!
Location
NE Ohio
Car(s)
2017 SE 6 MT
No, differential fluid for sure, see here at about the 3:20 mark:


If I knew "drive it around normally for 10-20 minutes to get it to the optimal temperature" or "drive until the oil temp reads 180, and the differential should be up to temp (68-104 degrees Fahrenheit") or whatever, then I could get this done before the weekend. I mean... lots of guys don't use torque wrenches on some things, do I really need the temp to be between 20-40C / 68-104F? I'd think too cold would be worse than too hot.
 

nomunic

Drag Racing Champion
Location
East Coast
Car(s)
MK7
No, differential fluid for sure, see here at about the 3:20 mark:


If I knew "drive it around normally for 10-20 minutes to get it to the optimal temperature" or "drive until the oil temp reads 180, and the differential should be up to temp (68-104 degrees Fahrenheit") or whatever, then I could get this done before the weekend. I mean... lots of guys don't use torque wrenches on some things, do I really need the temp to be between 20-40C / 68-104F? I'd think too cold would be worse than too hot.
I would recommend you hit that temp range, but I’ve also done it after waiting like 20 minutes after a long drive. By the time I wait and have it all jacked up I think the temp should be fine.
 

YamR1rider

Drag Racing Champion
Location
Tampa, FL
Car(s)
2017 GTI Sport DSG
Yep, for the VAQ diff, if you can, just wait till the ambient temperature is within the range. Of course you can warm it up and do all that....but bear in mind you are working right around the exhaust pipe - life is easier when its cold for this job.
 

victorofhavoc

Autocross Champion
Location
Kansas City
Yep, for the VAQ diff, if you can, just wait till the ambient temperature is within the range. Of course you can warm it up and do all that....but bear in mind you are working right around the exhaust pipe - life is easier when its cold for this job.
Agreed.

The drain and fill bolts are in awkward places, so I'd also recommend covering part of the subframe there with aluminum foil.

I personally don't see tremendous reasoning for warming things up other than making the fluid move a bit better. It's a gear fluid after all and moves like molasses. I've heated up various gear fluids before in metal containers with a torch (and a glove) to get them to move... Os giken is liked mud. Viscosity changes, but volume really doesn't. On the dsg it matters because there are so many nooks and crannies the fluid needs to fill so bubbles and fluid movement can mess with your fill.
 

BudgetPhoenix

Autocross Champion
Location
Kansas
Car(s)
2009 GLI, 2016 GTI
I think people way overthink the temp ranges when doing stuff like diff/trans. The range is pretty big just get the car warm and go for a drive and let it cool for a short while before you start and you should be okay. I don't even check it in vcds anymore. Just dont do it on a super cold engine and you should be good to go.
 
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enobiko

Ready to race!
Location
NE Ohio
Car(s)
2017 SE 6 MT
One problem... I live in NE Ohio, so waiting for the ambient temperature is... holy crap! The high will be 70 on Tuesday, and up to 77 on Thursday! I think I've found my window of opportunity! That's 25-30 degrees warmer than today's high. I'll leave the diff fluid and the tranny fluid in the sun to warm up... or maybe put them in a bucket of hot water. The 70W gear oil will flow much better when warm, at least, and it takes 5 times as much.
 

victorofhavoc

Autocross Champion
Location
Kansas City
One problem... I live in NE Ohio, so waiting for the ambient temperature is... holy crap! The high will be 70 on Tuesday, and up to 77 on Thursday! I think I've found my window of opportunity! That's 25-30 degrees warmer than today's high. I'll leave the diff fluid and the tranny fluid in the sun to warm up... or maybe put them in a bucket of hot water. The 70W gear oil will flow much better when warm, at least, and it takes 5 times as much.
For my other car i run an 80-250, and had to change it once in -10 Midwest weather. It took nearly 2 hrs with a blow torch for 1L, and that was after boiling water! Anything above 50F or so makes it much more manageable!!

70+ you'll be pretty good. Just make sure to do a dry run beforehand and 100% confirm you can reach AND CRACK the fill bolt. I ended up having to use 2 of my 6" extensions and a 3" wobble extension to reach the fill bolt and broke an extension in the socket in the process. My factory bolt was hard locked in there at 30k miles...
 

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enobiko

Ready to race!
Location
NE Ohio
Car(s)
2017 SE 6 MT
Thanks for the advice, all went well! The weather turned unseasonably warm, making this an easier task.
Except... When I went to do the tranny fluid as well, 10k early but so long as I had it up on 4 jack stands and level... But, I had heard some transmissions don't have fill plugs... mine didn't! Thanks to this group, I found a thread to remove the reverse detent spring, which allowed me to fill. Trouble is, I read to fill 2.45 quarts, then afterwards remembered I was using liters, so it should have been 1.3 liters. I drained a bit of fluid, but I wasn't accurate. How stupid to leave out a fill plug/fluid fill level overflow?
 

victorofhavoc

Autocross Champion
Location
Kansas City
Thanks for the advice, all went well! The weather turned unseasonably warm, making this an easier task.
Except... When I went to do the tranny fluid as well, 10k early but so long as I had it up on 4 jack stands and level... But, I had heard some transmissions don't have fill plugs... mine didn't! Thanks to this group, I found a thread to remove the reverse detent spring, which allowed me to fill. Trouble is, I read to fill 2.45 quarts, then afterwards remembered I was using liters, so it should have been 1.3 liters. I drained a bit of fluid, but I wasn't accurate. How stupid to leave out a fill plug/fluid fill level overflow?
If you're talking about the dsg, it's a bottom/pressure fill approach.
 

enobiko

Ready to race!
Location
NE Ohio
Car(s)
2017 SE 6 MT
Not DSG, I drive a manual. In fact... I have never owned a car that was not a manual! (I've driven an auto... and my wife's cars don't count as having been "mine".) Back in the 70's, autos were performance-sapping and MPG-sapping, but things have changed. I drove my nephew's GLI with DSG, I'm impressed! Still, love my manual.
 

victorofhavoc

Autocross Champion
Location
Kansas City
Not DSG, I drive a manual. In fact... I have never owned a car that was not a manual! (I've driven an auto... and my wife's cars don't count as having been "mine".) Back in the 70's, autos were performance-sapping and MPG-sapping, but things have changed. I drove my nephew's GLI with DSG, I'm impressed! Still, love my manual.
Yeah, manual is more fun. Dsg is definitely faster and easier to master on track with lfb and such. The one thing I regret about my car is that it's not manual :/
 
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