Rear end Oil 8 3/4" • The Dodge Challenger Message Board

by **mopar70** » 08 Jan 2006 9:15

Hi
I wounder what is the best Oil that I can put in my 8 3/4" with a slip diff?
do I need to put in some additive?
If I had to put in some additive how much off that?
and where to buy additive?

//Roland

by **Christer** » 08 Jan 2006 10:24

From what I have heard no additives are needed. You only need additives if you are going to drive it really had, then I mean really hard.

As for the oil I use Valvoline myself. I don´t know if it is good or not though. I haven´t testet it yet. :s022:

by **dave-r** » 08 Jan 2006 12:03

With a sure grip you need additive if you use normal gear oil.

You can get limited slip diff oil in large cans from oil plants that have retail outlets. It is real cheap that way. Farmers use it in their tractors and some heavy plant use it.

You need an oil of SAE 90 grade. If you can't get oil with the additive already in a Mopar Performance dealer will sell you the additive. Some other motor factor outlets sell additives that will work too.

by **mopar70** » 08 Jan 2006 16:51

Hi
I dont know but I have read on a lot of oil for the rear end that the oil is for the limited slip diff does they work without additive or should I add the additive in the oil?

I have some problem with my axel because the diff dont seam to work correct every time once a while only the right tire spin and the left dont grip, what can be wrong it is a 8 3/4" with 489 house, my friend have the same problem with his axel.

//Roland

by **mopar70** » 08 Jan 2006 17:02

I forgott to tell you what oil I use is it
Quaker State High Performance 80W-90 for limited slip diff

link for the oil:
http://www.pzlqs.com/Tech/Pdsheet/Quake ... ricant.PDF

//Roland

by **dave-r** » 08 Jan 2006 18:19

Sounds like either the limited slip is worn or it has not got a limited slip fitted.

by **mopar70** » 08 Jan 2006 18:46

there is a limited slip fitted but maby it is worn, I will change the house anyhow because I will put in another gear, I will built a new 489 or 472 house with 3.91 gear in it.

//Roland

by **dave-r** » 08 Jan 2006 18:59

One of the reasons for fitting an additive is to stop it wearing. :wink:

I just put together a 742 for a freind of mine with auburn gear LSD and 3.55:1 gears to replace the open 3.23:1 he had before. He is very pleased with it.

by **mopar70** » 08 Jan 2006 20:11

how much did you give for a new auburn and a gear set,
maybe I rebuild min 489 with a new diff and a new gear set.
//Roland

by **dave-r** » 08 Jan 2006 21:10

My friend paid for the parts so i don't know what they cost. I just put them together for him.