Differential fluid work---Amsoil
Thread Starter
Burning Brakes
Joined: Apr 2007
Posts: 754
Likes: 0
From: North Carolina
Differential fluid work---Amsoil
Brad Pmd me about his amsoil products. Never tried it but it seems good. Hes going to give me a deal on the synthetic differential fluid. My fluid has never been changed in its life. That got me thinking because I saw post on here about diffs going out but thas because of dragging. My car has over 120,000 miles on it. When I first purchased it, the fluids has not been changed in a year and a half. It sat for that long. We bought it from a dealership who the owner is good friends with daddy. I personally believe that is why my tranny, engine, and cooling system came out ****y in the long run. Quiestion is, if I change the fluid, will this be enough or do I need to add something else? Am buying two quarts of the synthetic something. Don't rememer but he does. How exactly do I do the fluid change and is it hard? Need details though. Thanks.
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Joined: Aug 2001
Posts: 5,364
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From: King George VA
N.C. Kid,
The fluid is this one:
AMSOIL Severe Gear Extreme Pressure Synthetic 75w90
I'll defer to the C4 experts on changing the fluid. I've read that some of the early C4 diff's don't have drain plugs on the bottom like the C5 does, but I'm not sure if that goes for the whole model run. I know I've read some how-to's on changing the C4 diff fluid, so hopefully someone will chime in for you.
The fluid is this one:
AMSOIL Severe Gear Extreme Pressure Synthetic 75w90
I'll defer to the C4 experts on changing the fluid. I've read that some of the early C4 diff's don't have drain plugs on the bottom like the C5 does, but I'm not sure if that goes for the whole model run. I know I've read some how-to's on changing the C4 diff fluid, so hopefully someone will chime in for you.
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C66 Racing #66 NASA ST2, SCCA T2
AMSOIL Dealer (Forum Vendor)
AMSOIL Preferred Customer Program (Members buy at Wholesale - a savings of about 25%)
Race Director
Joined: Jun 2005
Posts: 17,640
Likes: 1
From: Lenoir City TN
St. Jude Donor '08-'09-'10-'11
Early C4's do not have drain plugs, some members install drain plugs, some actually will suck most of the fluid out of the fill hole.
I lowered the rear enough to allow the batwing to come out, removed it from the pumpkin, out came the fluid, cleaned everything up inside, installed batwing with 'The Right Stuff' sealer, installed two bottles of GM additive and topped off w/ Mobil 1 synthetic, not familiar w/ Amsoil.
Bob
I lowered the rear enough to allow the batwing to come out, removed it from the pumpkin, out came the fluid, cleaned everything up inside, installed batwing with 'The Right Stuff' sealer, installed two bottles of GM additive and topped off w/ Mobil 1 synthetic, not familiar w/ Amsoil.
Bob
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Diff fluid should really only be changed after it's broken in from the factory. After that it's not an issue. A year and a half is nothing.
No C4s have drain plugs.
Get a cheap plastic pump from autozone and buy some longer clear tubing to attach to the suction end of it, stick that in the fill hole.
Anyways, enjoy your leaks. IMO, you'll be lucky if the factory RTV holds up against the synthetic.
No C4s have drain plugs.
Get a cheap plastic pump from autozone and buy some longer clear tubing to attach to the suction end of it, stick that in the fill hole.
Anyways, enjoy your leaks. IMO, you'll be lucky if the factory RTV holds up against the synthetic.
Thread Starter
Burning Brakes
Joined: Apr 2007
Posts: 754
Likes: 0
From: North Carolina
Diff fluid should really only be changed after it's broken in from the factory. After that it's not an issue. A year and a half is nothing.
No C4s have drain plugs.
Get a cheap plastic pump from autozone and buy some longer clear tubing to attach to the suction end of it, stick that in the fill hole.
Anyways, enjoy your leaks. IMO, you'll be lucky if the factory RTV holds up against the synthetic.
No C4s have drain plugs.
Get a cheap plastic pump from autozone and buy some longer clear tubing to attach to the suction end of it, stick that in the fill hole.
Anyways, enjoy your leaks. IMO, you'll be lucky if the factory RTV holds up against the synthetic.
Bradshaw, dont you have something that WONT leak. I was trying to keep it alive not leak and kill it.
Thread Starter
Burning Brakes
Joined: Apr 2007
Posts: 754
Likes: 0
From: North Carolina
Diff fluid should really only be changed after it's broken in from the factory. After that it's not an issue. A year and a half is nothing.
No C4s have drain plugs.
Get a cheap plastic pump from autozone and buy some longer clear tubing to attach to the suction end of it, stick that in the fill hole.
Anyways, enjoy your leaks. IMO, you'll be lucky if the factory RTV holds up against the synthetic.
No C4s have drain plugs.
Get a cheap plastic pump from autozone and buy some longer clear tubing to attach to the suction end of it, stick that in the fill hole.
Anyways, enjoy your leaks. IMO, you'll be lucky if the factory RTV holds up against the synthetic.
Reread your post. You must have misunderstood me. The differential fluid has NEVER been changed from what I was told. The antifreeze, oil and tranny fluid sat for a year and a half. Why, I am not sure but its all good now. Just need to work on the rearend. Dont want the synthetic if its going to cause leaks.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
GM doesn't have a change interval for the rear, which is probably why there's no drain plug.
If your diff is bone dry now, you might be okay with synthetic. I pulled my diff eventually because M1 made it leak ridiculously bad. I removed the cover and there were parts with no RTV at all. And what was left simply came off in my fingers, there was no adhesion to the aluminum.
I put some standard issue Valvoline 80w90 in there. I can only speak from my experience on this one. Maybe others with actual experience will chime in before the regurgitators do.
If your diff is bone dry now, you might be okay with synthetic. I pulled my diff eventually because M1 made it leak ridiculously bad. I removed the cover and there were parts with no RTV at all. And what was left simply came off in my fingers, there was no adhesion to the aluminum.
I put some standard issue Valvoline 80w90 in there. I can only speak from my experience on this one. Maybe others with actual experience will chime in before the regurgitators do.
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Race Director
Joined: Jan 2005
Posts: 10,641
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From: Slidell Louisiana
Use the synthetic, if everythings in good shape it SHOULD NOT LEAK.
I used Mobile one gear lube in mine. (no leaks yet but it has only been a little more than two years since the synthetic lube was added) however, I replaced the three oil seals and used the right stuff during my d-44 install with synthetic lube.
I used Mobile one gear lube in mine. (no leaks yet but it has only been a little more than two years since the synthetic lube was added) however, I replaced the three oil seals and used the right stuff during my d-44 install with synthetic lube.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Why shouldn't it? I think synthetic washed off the factory RTV. "The Right Stuff" on the other hand, is obviously superior to what GM used. I don't think the OP wants to pull the diff, which is the half the point in asking for what fluid to use.
Race Director
Joined: Jun 2004
Posts: 13,961
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From: WI
Tech. tips will help you. They are under the Other tab at the top.
https://www.corvetteforum.com/techti....php?TopicID=2
https://www.corvetteforum.com/techti...D=48&TopicID=2
C4 Rear Axle Recommended Maintenance -- 1 of 1
Date Published: 2001-06-14
Submitter's Name: Tod DeBie
Email Address:
Corvetteforum.com Member Alias:
The rear axels in C4 Corvettes are from Dana Corporation http://www.dana.com/
GM does not specify a service interval in the owners manual. Dana Corporation makes the following recommendations:
1. If there is any possibility of water contamination the oil needs to be changed immediately.
2. If the axle temperature spend a lot of time at or above 275F, the oil should be changed every 30,000 miles and the set up and bearings should be checked every time. This should only be a factor when you are getting a good amount of track time.
3. Under normal use, the oil should be changed at 75,000 miles.
4. If you are getting chatter (noise) from the rear end, you may want try changing the oil or at least adding some limited slip additive.
Dana Corp says that the factory oil is adequate, but synthetics are superior especially when heat is an issue. A limited slip additive should always be used. Gear oil should have a GL-5 rating and a 75w-140 or 75w-90 weight, with 75w-140 being the preferred weight.
https://www.corvetteforum.com/techti....php?TopicID=2
https://www.corvetteforum.com/techti...D=48&TopicID=2
C4 Rear Axle Recommended Maintenance -- 1 of 1
Date Published: 2001-06-14
Submitter's Name: Tod DeBie
Email Address:
Corvetteforum.com Member Alias:
The rear axels in C4 Corvettes are from Dana Corporation http://www.dana.com/
GM does not specify a service interval in the owners manual. Dana Corporation makes the following recommendations:
1. If there is any possibility of water contamination the oil needs to be changed immediately.
2. If the axle temperature spend a lot of time at or above 275F, the oil should be changed every 30,000 miles and the set up and bearings should be checked every time. This should only be a factor when you are getting a good amount of track time.
3. Under normal use, the oil should be changed at 75,000 miles.
4. If you are getting chatter (noise) from the rear end, you may want try changing the oil or at least adding some limited slip additive.
Dana Corp says that the factory oil is adequate, but synthetics are superior especially when heat is an issue. A limited slip additive should always be used. Gear oil should have a GL-5 rating and a 75w-140 or 75w-90 weight, with 75w-140 being the preferred weight.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
I'd trust Dana over them any day of the week.
