Recommender Diff Oil for 75 C3
Thread Starter
Heel & Toe
Joined: May 2012
Posts: 16
Likes: 0
From: Gold Coast Queensland
Recommender Diff Oil for 75 C3
Guys I live in Australia and I am looking for a suitable oil replacement the diff and 4 speed Gbox.
Can you guys offer some recommendations.
Thanks for the help.
Cheers,
Paul
Can you guys offer some recommendations.
Thanks for the help.
Cheers,
Paul
Melting Slicks
Joined: Sep 2004
Posts: 3,227
Likes: 671
From: Northeast
When I changed the fluid in my Borg Warner 4spd, I used Mobil 1 75w-90 synthetic. Does seem to shift smoother.
I searched the internet about possible problems & no one could provide before and after pics of what would happen. They talked but no proof. Something about degrading the metals. Brass, red, yellow
Or just go with what the owner's manual recommends.
As far as the diff, I used regular gear lubricant. An expert steering and diff rebuilder on this forum recommended 85w-140 with the additive so that is what I did. Seems good so far.
I searched the internet about possible problems & no one could provide before and after pics of what would happen. They talked but no proof. Something about degrading the metals. Brass, red, yellow
Or just go with what the owner's manual recommends.
As far as the diff, I used regular gear lubricant. An expert steering and diff rebuilder on this forum recommended 85w-140 with the additive so that is what I did. Seems good so far.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
When I changed the fluid in my Borg Warner 4spd, I used Mobil 1 75w-90 synthetic. Does seem to shift smoother.
I searched the internet about possible problems & no one could provide before and after pics of what would happen. They talked but no proof. Something about degrading the metals. Brass, red, yellow
Or just go with what the owner's manual recommends.
As far as the diff, I used regular gear lubricant. An expert steering and diff rebuilder on this forum recommended 85w-140 with the additive so that is what I did. Seems good so far.
I searched the internet about possible problems & no one could provide before and after pics of what would happen. They talked but no proof. Something about degrading the metals. Brass, red, yellow
Or just go with what the owner's manual recommends.
As far as the diff, I used regular gear lubricant. An expert steering and diff rebuilder on this forum recommended 85w-140 with the additive so that is what I did. Seems good so far.
I use Amsoil Severe gear 75-90 no posi lube, never an issue or chatter. There are other weights available and posi lube if needed here. http://www.amsoil.com/shop/by-product/gear-lube/
Subdriver on the forum is a good supplier and you get a price break.
Melting Slicks
Joined: Sep 2004
Posts: 3,227
Likes: 671
From: Northeast
No Brass in the diff. I use Amsoil Severe gear 75-90 no posi lube, never an issue or chatter. There are other weights available and posi lube if needed here.
http://www.amsoil.com/shop/by-product/gear-lube/
Subdriver on the forum is a good supplier and you get a price break.
I use Amsoil Severe gear 75-90 no posi lube, never an issue or chatter. There are other weights available and posi lube if needed here. http://www.amsoil.com/shop/by-product/gear-lube/
Subdriver on the forum is a good supplier and you get a price break.
So you use the same in both? and dont worry about the transmission parts?
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Le Mans Master
Joined: Oct 2007
Posts: 7,462
Likes: 985
From: RI, Now Franklin/Nashville TN
I have been using the Mobil 1 75W-90 in my 4 speed as well since 1990-no issues.
Drifting
Joined: May 2012
Posts: 1,353
Likes: 44
From: Calgary Alberta
GM 75-90 synthetic in the diff of my 70 with one bottle of GM posi additive like the manual says, and the car loves it.
Trans has GM 80-90 gear oil, dino. Considering moving to synthetic, undecided.
Trans has GM 80-90 gear oil, dino. Considering moving to synthetic, undecided.
Le Mans Master
Joined: Oct 2007
Posts: 7,462
Likes: 985
From: RI, Now Franklin/Nashville TN
I changed the gear box fluid recently for the second time with Mobil 1 75W-90 (the first time was in the early 90's) and I drained the fluid using the bottom drain plug on the side of the tranny and filled from the top plug until the fluid begins to run out of the hole. My 4 speed takes about 1.5 quarts of fluid. Hope that helps!
Safety Car
Joined: Sep 2011
Posts: 4,121
Likes: 1,231
From: Madeira Beach, FL
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I do not know what you have in the way of automotive parts stores.
At Napa in the USA, I purchased their 85-90 syntech, synthetic blend.
I filled my M-20 gearbox till it just started to run out of the upper fill hole.
I have no lower drain hole so it had to be manually suctioned out.
Boy that really sucked
The rear is special with clutches so use the recommended weight and posi lube additive.
All very good advise on earlier posts by experienced members.
After adding new fluids make a series of figure 8's both clockwise and counter clockwise.
I thought this was silly but it was rec in order to get the new rear lube moved around in the clutch plates.
I saw it on here and figured it cost me nothing to try so I did it.
After all if its on the internet it must be true
Happy New Years,
Marshal
At Napa in the USA, I purchased their 85-90 syntech, synthetic blend.
I filled my M-20 gearbox till it just started to run out of the upper fill hole.
I have no lower drain hole so it had to be manually suctioned out.
Boy that really sucked
The rear is special with clutches so use the recommended weight and posi lube additive.
All very good advise on earlier posts by experienced members.
After adding new fluids make a series of figure 8's both clockwise and counter clockwise.
I thought this was silly but it was rec in order to get the new rear lube moved around in the clutch plates.
I saw it on here and figured it cost me nothing to try so I did it.
After all if its on the internet it must be true
Happy New Years,
Marshal
