The past couple of times I changed the rear diff I used 75W90 Mobil 1 Hypoid Gear Oil.

Lately I have read a bunch of things about multi viscosity fluids being used in rear diffs as not a great idea because our specs are a straight 90W hypoid gear oil and the lower 75 might not be up tot he task. - http://www.lubrizol.com/products/automotiv...ar-oil/J306.asp

As my car gets plenty of track work I wanted to ask here and not under the hood.

What are you guys putting in your rear diffs?

 

I'm thinking of trying the LE-1605, thoughts?

http://www.hardtopguy.com/store/prod...?productid=252

 

I've used that for years with no issues. I'm not worried about continuing to use it, even though the actual spec is for a 90W oil.

 

I run the redline stuff...no problems

 

Motul 75w-90

 

The SAE 90 spec for the diff was written in 1999.
In those days that SAE 90 spec was wider then it is today, up to what now is called SAE 140, as you can see on the lubrizol website you linked to.
Also, Honda recommended the GL-6 spec that was intended to be used in high offset ring & pinion final drives (but never became official)

Triple-H Posted on Jul 9 2008, 08:50 PM
Its not the 75W by itself that's the "problem" but the additives needed to reach the cold flow / pour point specs.
Those pour point additives are not lubricants.
Single grade oils (like the LE-1605) don't have them

I'm using Amsoil SAE 190 now in my 4.57 diff and it made it a little less noisy.
I've been to only 3 trackdays, the last one with the Amsoil.

 

LE1605 here 607 before that

 

I have used LE-607 (SAE-90 GL-5) in my differential since I got the car. I autocross but I don't track the car.

I'm curious about when/where/how Honda recommended GL-6. My 2005 factory service manual specifies GL-5 SAE-90.

I am also confused by the inclusion of "LE1605" in the item title on the hardtopguy link, which shows LE607. I remember someone mentioning LE1605 before, and I checked the LE web site and found that LE1605 is a different product with totally different specs.

 

Orthonormal Posted on Jul 9 2008, 11:14 PM

This is a scan from my MY00 (German) manual.

LE-607 is discontinued and the LE-1605 is the replacement.
The 607 was pretty thick and would now be called a SAE 110, the 1605 IS called a SAE 110.
Both within range of the original SAE 90 spec (in 1999)

All multigrades are also within range, at the thinner end of it.

 

I run Neo Synthetic RHD 75/90 in mine. We had some significant temp issues and this was recommended by ATS as an alternative sice the ATS fluid would not stand up to the temps we were seeing.