I need advice. I went to day to my local dealer to buy the diff fluid additive for the limited slip. To start out the sales man in the counter dint know what was the oil additive I was asking for fine. I explained and then some one else help him out and he finally found the stuff. Then I ask him how much was recommended. He then tells me that is 2 quarts of the 75-90 and I tell him no that’s not Wright because. I had the vehicle service and I had the diff fluid change and I recently went on a trip for 600 miles and my diff blew the fluid out. He then tells me wait one second I will ask our master mechanic.
He comes back and tells me that it is not required to have the limited slip additive. He tells me that the oil that they sell already has it. Well I left clueless I need to know.
1 how much fluid does the diff takes and the correct weight.
2 do I need the additive or not because today’s fluids come whit it all ready.
3 what’s the best out there for my diff.
My car is a 2003 vert 6spd
I only have 25,000 miles on it.
Also I don’t know if this is important I got 540 torque @ the wheels.
Which I the need help whit this question. I was told that I am not suppose to drive whit the limited slip on my friend told me to always turn in off but not all the way to competition mode. True or false.

 

What are you saying. (or trying to say)

Some diff fluids available already have the additive. You just need to check to be sure.

You can NOT turn off limited slip. You can turn off traction control (electronics) or you can turn off Active Handling and Traction Control (Bad Idea)

btw...Spell check can be your friend.

 

I know my inglish sucks. what i meant was traction control he told me that i have too much torqe and i will mess up the diff if i leave it on

 

He's WRONG

Also unless you're FI you have no where close to 540 torque at the wheels.

 

i am FI the car got lots of toys on. I really need to know how much fluid and do i need the oil aditive or not

 

According to GM, the diff holds 1.69 qts. Buy two quarts of any of the well known gear lubes and add the additive ONLY if the gear oil DOES NOT ALREADY CONTAIN IT.

Note: IF, and I repeat IF you experience any chattering from the diff after changing, then and ONLY then should you add some additional limited slip additive. If you DO add, add only in small amounts at a time, road-testing the car each time. The LAST thing you want is too MUCH additive.

I like Amsoil SVG 80W-90. It already has additive in it. There are other good brands out there too that also have the additive in them as well.

 

I'm a little confused. In your profile it says you have 349 hp at the rear wheels. I'm not sure how you could have 540 lbs ft of torque???

 

I noticed that too.

 

old numbers i havent up dated this forum since i wet FI my bad
new nubers 560 hp 540 tq @ wheels.

 

I just changed the diff fluid in my 2000 used Amsoil Two Amsoil distributers said I should not need the additive because theirs has it in it but if any noise go ahead and put in only 2-2.5 ounces (not 4 ) which is what I have always known too much he said can have an adverse affect (Amsoil's additive) After driving a few hund. miles I think I need the additive. Its a little noisier back there now

 

What????????

 

Easy answer for you...

2 quarts of Royal Purple 75/90 and 1 bottle of GM Limited slip.

You will use almost all of the second bottle.

Jason