I guess OE is Diaqueen

vs.

Amsoil Severe Gear 75W-90
http://www.amsoil.com/catalog.aspx?code=SVGQT-EA

For my 05 GSR.

I know many people are very firm to say ONLY Diaqueen in the t-case, but I don't really know why the Severe Gear wouldn't work.

HELP!

 

Either one is fine. You want a GL-5 fluid for the transfer case. A quick search and you will find the recommended fluids.

 

Either will work, you'll find plenty of people who run both without issue.

 

I just had my T-case rebuilt by Shepherd and Trevor told me NOT to use amsoil (which I have already purchased). Now I am pretty worried, do I really need Diaqueen or is he misinformed?

 

Trevor is amongst the least misinformed when it comes to Evo TC's and Transmissions. Trevor, Jon Shephard, Jon @ TRE and Jack @ Jacktransmisisons have all recommended me OE Diaqueen for my TC, so I see no reason to use anything else.

 

Well crap, so I cannot use my amsoil for sure? Does anyone have any reasoning behind this? I use amsoil in everything else and its amazing.

 

I'm using Redline heavy weight shockproof @ SAE 75W250 for 3 years with no issues. It’s a tad thicker then Amsoil Severe Gear 75W-90

By all means, I'm no expert in analyze fluids. I personal like the thicker fluids because it has to protects better at higher temperatures keeping the fluid stable. With that said, you can't go wrong with Diaqueen.

 

You also have to consider the film strength of the oil. A good quality thinner oil may have a very strong film strength and still protect very well.

 

I'm not saying, but I'm just saying I ran Redline 75w90 back in 2003-2004 and destroyed two transfer cases just driving to Portland and back. Now there could have been many other factors involved (not full enough, etc etc) but on the 3rd transfer case I ran straight 90 weight (which is what it calls for) and never had another issue. On my 06 Evo I've been running 90w and its been fine since. If I change from 90w I'll run something like the 75W250.

 

According to my Amsoil dealer friend Amsoil specifically warns against using their product in the Evo's drivetrain. I'll see if I can get him to chime in b/c I don't know the specifics of why or where they stated this.

 

^ correct I think if you go to the Amsoil website, plug your 03-06 Evo into the wizard, it will say there is no compatible transfer case fluid.

 

Well damn, Diaqueen is expensive!!

 

The only other recommended aftermarket gear fluid to use in t-case and rear diff is Motul 90PA. I have it in my EVO X without any issue and the car seems to be smoother.

 

I use amsoil fluid for oil and in my tranny/rear diff. Up until now, no one told me this was an issue so I am a bit uneasy at the moment. At the end of the day, I do not want to take a risk, so I will put in whatever is required.

 

that it is! try and get some buddies that need to change their fluid to go in on a full jug, much cheaper and you might have some left over at the end. I went that route and I think we even got a deal for buying in bulk.