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DIY: manual transmission and rear differential fluid service

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DIY: manual transmission and rear differential fluid service

 
Old 10-21-2017, 08:18 PM
  #41  
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Why are you changing the differential fluid and transmission fluids with such low mileage? GM recommends changing the rear axle fluid at 45,000 mile and the transmission fluid @ well actually the manual does not even show a required fluid change.

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Old 10-21-2017, 08:25 PM
  #42  
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GM's transmission fluid isn't anything special so a new high-quality fluid makes the transmission shift MUCH smoother. Changing out the rear differential fluid early is never a bad idea since it removes all the initial break-in materials and shavings. The factory-fill fluid is typically the only time you'll see the silver metallic sheen in the drained gear oil.
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Old 10-21-2017, 08:35 PM
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Was going to say it Maxie, but the OP just said it for me. Believe me, with high performance cars you drive hard, you will not regret it. Btw, is that a new c7 in your avatar pic or the one you’ve had?

I have the trans fluid, full synthetic, waiting for spring, before I bring it out. Damn M7 is awesome, but notchy in this thing. Same with my M6 Camaro. Changed the fluid from the factory crap and that TR6060 became amazing and silky smooth

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Old 10-21-2017, 10:44 PM
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Originally Posted by Kracka View Post
GM's transmission fluid isn't anything special so a new high-quality fluid makes the transmission shift MUCH smoother. Changing out the rear differential fluid early is never a bad idea since it removes all the initial break-in materials and shavings. The factory-fill fluid is typically the only time you'll see the silver metallic sheen in the drained gear oil.
I wonder if this applies to the auto transmission too?
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Old 10-22-2017, 09:04 AM
  #45  
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Originally Posted by Maxie2U
Why are you changing the differential fluid and transmission fluids with such low mileage? GM recommends changing the rear axle fluid at 45,000 mile and the transmission fluid @ well actually the manual does not even show a required fluid change.
Owners manual says to change the diff fluid after the first track day.
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Old 10-22-2017, 09:07 AM
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Originally Posted by Maxie2U View Post
I wonder if this applies to the auto transmission too?
It does, but changing out the automatic transmission fluid isn't quite as easy of a DIY job so you may want to let the dealer or shop tackle it. My suggestion would be Redline D6 ATF for a high-quality full-synthetic fluid. For this, I would suggest change intervals of every 30-45k miles (so not as frequently as manual transmission fluid).

Last edited by Kracka; 10-22-2017 at 09:08 AM.
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Old 10-22-2017, 03:34 PM
  #47  
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Most of what you see coming out in diff fluid I believe is carbon fiber particles from the clutch wearing in. It's kind of thick and sticky.
I've got 7,000 miles and just changed to 4th diff fluid with mostly track use. Also on 3rd tranny fluid. GM recommends to change diff fluid after every 20 track hours. I like to keep the fluids in new condition and send samples out frequently for testing to feel confident to hammer away.

Much easier to change it and sleep well than argue over conviencing myself that I don't need to do it.

All bets are off if it is a waxer or garage Jewelry.

Last edited by Kamran; 10-22-2017 at 03:41 PM.
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Old 10-22-2017, 03:49 PM
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Originally Posted by Kamran View Post
All bets are off if it is a waxer or garage Jewelry.
Factory lifetime fill fluid

Last edited by Kracka; 10-22-2017 at 03:49 PM.
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Old 10-22-2017, 04:51 PM
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Originally Posted by ls3zob View Post
Was going to say it Maxie, but the OP just said it for me. Believe me, with high performance cars you drive hard, you will not regret it. Btw, is that a new c7 in your avatar pic or the one you’ve had?
Avatar is a pic of my 2016 the day I picked it up back in Oct '15.
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Old 11-18-2017, 01:25 PM
  #50  
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Thanks for posting this DIY. J just flushed the rear diff on my z06 with this. I used about 2.999 quarts of the mentioned 75w90 GM oil and the Plews pump on Amazon. I was able to reach the fill plug without a flex head ratchet by utilizing 3.500" of extension; this facilitated using a torque wrench to finish the process.
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Old 11-18-2017, 10:26 PM
  #51  
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My question is; if I used Redline D4 and then had a transmission failure would GM still warranty the transmission or void the warranty?
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Old 11-19-2017, 08:21 AM
  #52  
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Originally Posted by Maxie2U View Post
My question is; if I used Redline D4 and then had a transmission failure would GM still warranty the transmission or void the warranty?
It's a major petroleum company's fluid that meets Dexron III spec, I see no reason why they wouldn't honor the warranty.
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Old 11-20-2017, 12:14 PM
  #53  
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Originally Posted by lrobe22 View Post
I was able to reach the fill plug without a flex head ratchet by utilizing 3.500" of extension
Now that my friends is a very precise extension. I'm lucky to have more than 1 decimal of precision
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Old 11-20-2017, 12:57 PM
  #54  
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Originally Posted by muncie21 View Post
Now that my friends is a very precise extension. I'm lucky to have more than 1 decimal of precision
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Old 12-26-2017, 01:31 PM
  #55  
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Thanks for the DIY. I want to to ask a couple questions regarding the use of Mobil 1. Went to AutoZone today trying to buy the transmission oil from Mobil 1 but it said for automatic transmission only. I have a 2015 C7Z manual. So, is it ok to use that?

Second, I saw they have Mobil 1 75-90 but, online I saw some posts said that Mobil1 gear oil 75-90 would need the friction modifier added to it. Is that true?

I’d have gone with Redline but couldn’t find any around. And I’ve been using Mobil1 on all my cars. But they’re not a Corvette so, I can take chances on them.
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Old 12-26-2017, 02:52 PM
  #56  
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Originally Posted by Phudu2004 View Post
Thanks for the DIY. I want to to ask a couple questions regarding the use of Mobil 1. Went to AutoZone today trying to buy the transmission oil from Mobil 1 but it said for automatic transmission only. I have a 2015 C7Z manual. So, is it ok to use that?

Second, I saw they have Mobil 1 75-90 but, online I saw some posts said that Mobil1 gear oil 75-90 would need the friction modifier added to it. Is that true?

I’d have gone with Redline but couldn’t find any around. And I’ve been using Mobil1 on all my cars. But they’re not a Corvette so, I can take chances on them.
Order the Redline fluid online. Amazon prime!
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Old 12-26-2017, 03:43 PM
  #57  
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Thanks for DIY, I just did the tranny and diff fluid yesterday. For the tranny fill/drain plugs, they have some sort of orange seal on the threads, much like how you wrap Teflon tape around the threads on pipe fittings. Are these plugs ok to reuse as is with NO reapplication of the orange seal?

The manual shows the tranny as having a 100k mile service interval, pretty much a sealed unit. Maybe that’s why they used those type of plugs?

Last edited by Pineapple; 12-26-2017 at 03:45 PM.
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Old 12-26-2017, 03:58 PM
  #58  
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Originally Posted by Pineapple View Post
Thanks for DIY, I just did the tranny and diff fluid yesterday. For the tranny fill/drain plugs, they have some sort of orange seal on the threads, much like how you wrap Teflon tape around the threads on pipe fittings. Are these plugs ok to reuse as is with NO reapplication of the orange seal?

The manual shows the tranny as having a 100k mile service interval, pretty much a sealed unit. Maybe that’s why they used those type of plugs?
Yes you can reuse. I did with no adverse effects.
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Old 12-28-2017, 08:08 AM
  #59  
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Originally Posted by FYREANT View Post
Order the Redline fluid online. Amazon prime!
Walmart.com has free 2-day shipping as well, this is where I got my most recent jug of Redline ATF D4.
Originally Posted by FYREANT View Post
Yes you can reuse. I did with no adverse effects.
Agreed. I've reused mine twice now without adding any additional thread sealant and am experiencing no leaks of any sort.

Last edited by Kracka; 12-28-2017 at 08:08 AM.
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Old 12-28-2017, 08:11 AM
  #60  
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Originally Posted by Phudu2004 View Post
Thanks for the DIY. I want to to ask a couple questions regarding the use of Mobil 1. Went to AutoZone today trying to buy the transmission oil from Mobil 1 but it said for automatic transmission only. I have a 2015 C7Z manual. So, is it ok to use that?

Second, I saw they have Mobil 1 75-90 but, online I saw some posts said that Mobil1 gear oil 75-90 would need the friction modifier added to it. Is that true?
This is the correct Mobil 1 gear oil for the rear differential: https://mobiloil.com/en/gear-lubrica...c-gear-lube-ls
It already contains the friction modifier, but additional additive might be needed in certain applications.

Here is the correct Mobil 1 ATF for the M7 manual transmission: https://mobiloil.com/en/automatic-tr.../synthetic-atf

Last edited by Kracka; 12-28-2017 at 08:14 AM.
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