# manual tramsmission fluid



## jmd (Sep 29, 2006)

which is best to use and what weight. can you use the same for differential oil? tks


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## Gregscalade (Dec 6, 2006)

don't use diff oil

GM recommends Dex III ATF, I believe. Just use a good synthetic.


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## b_a_betterperson (Feb 16, 2005)

Greg's right. A Dexron III's in there now. You can with replace it with a Dexron III or Dexron VI ATF fluid. Royal Purple or Mobil 1 ATF are your best bets. You'll need 4.6 quarts of it. Do a search and you'll find info on how to change the fluid -- as it's an interesting procedure, to say the least.


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## jmd (Sep 29, 2006)

tks for the advice everyone.


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## bergenfelter (Nov 11, 2005)

If you live in a colder climate, I would recc. the Mobil 1 Dex III ATF for the manual tranny. My M6 shifted a bit stiff when it was cold with the stock dino oil in it from the factory. With the Mobil 1 synthetic, the cold shifting was vastly improved.

John.


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## SANDU002 (Oct 13, 2004)

Ditto on using Royal Purple for M6. Car shifts smoother in all weather conditions.


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## DrFix2Fly (Oct 27, 2004)

A quick call to Royal Purple today got me their recommendation to use their Synchromax in the tranny instead of their ATF. Either will work, but I was assured better performance from the Synchromax.


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## oldsow (Aug 6, 2006)

I used the RP Synchromax, made a difference , quiter and smoother shifting in M6 tranny.
For Diff lube I used Amsoil 75w-140 when I did the Harrop cover.


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## kegbelly (Mar 23, 2006)

DrFix2Fly said:


> A quick call to Royal Purple today got me their recommendation to use their Synchromax in the tranny instead of their ATF. Either will work, but I was assured better performance from the Synchromax.


For my 2006 GTO with manual 6-speed...Is the RP Synchromax what I need for a trans fluid change? Does it meet the manufacturer's specs? I'm still under warranty and need to stay that way.
Next stupid question: where to buy? RP's website shows o'reilly auto parts as about the only dealer in my area, but I went to o'reilly's website and I can find nothing on "royal purple", tried about 6 different searches.


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## DrFix2Fly (Oct 27, 2004)

Your owner's manual will say to use ATF, but RP SYnchromax exceeds requirements. I ordered mine through Jegs to include 5 quarts of Syncrhrmax, 2 quarts of diff oil and 6 quarts of engine oil. All about $120 to my door and a couple of hours to do the service. Enjoy the results and have a happy new year.


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## kegbelly (Mar 23, 2006)

DrFix2Fly said:


> Your owner's manual will say to use ATF, but RP SYnchromax exceeds requirements. I ordered mine through Jegs to include 5 quarts of Syncrhrmax, 2 quarts of diff oil and 6 quarts of engine oil. All about $120 to my door and a couple of hours to do the service. Enjoy the results and have a happy new year.


Thanks. Just want to avoid any warranty issues in the event I ever need the trans worked on.


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## oldsow (Aug 6, 2006)

the RP won't void warranty, in fact the dealership put mine in for me. You can order it off line or get it from O"reillys. they carry it. call one up and if they don't have it tell them to order it in for ya. only took mine one day to get.
if I remember right your M6 tranny holds 9.3 pints, So about 4 1/2 quarts you need so buy 5. Good stuff.


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## Subdriver (Dec 28, 2004)

jmd said:


> which is best to use and what weight. can you use the same for differential oil? tks


Applicable AMSOIL products if you are interested:
Tranny: AMSOIL ATF
Note: This fluid has just been reformulated to meet the newer GM Dexron VI specification and is still backwards compatible with the older Dexron III spec.
Diff: AMSOIL Severe Gear Extreme Pressure Synthetic 75w140
:cheers


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## Jaybird48 (Feb 25, 2021)

b_a_betterperson said:


> Greg's right. A Dexron III's in there now. You can with replace it with a Dexron III or Dexron VI ATF fluid. Royal Purple or Mobil 1 ATF are your best bets. You'll need 4.6 quarts of it. Do a search and you'll find info on how to change the fluid -- as it's an interesting procedure, to say the least.


If it's supposed to be on level ground and it needs to be jacked up how do I get accurate reading?


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## Jaybird48 (Feb 25, 2021)

Jaybird48 said:


> If it's supposed to be on level ground and it needs to be jacked up how do I get accurate reading?


Is there a video anywhere of how its done?


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