Is 140w gear oil too thick?
 

I've been looking around for gl-4 gear oil and so far all I've found is oreilly brand straight 140. Just wondering if that would be too thick for the KA trans.

I am using straight Redline lightweight shockproof in my trans, and it seems to like it. Lightweight shockproof has the film strength of 75w140, but lower fluid friction.

The problem with heavy normal gear oil is it normally sucks when cold, and has higher fluid friction which robs horsepower.

Wow I sound like a Redline oil brochure.

But alas, don't run that junk in your trans! Buy some good stuff, it's not like you're going to change it anytime soon. PM me if you don't have a local retailer.

I have always searched for alternatives, but after some tries the redline mt90 is the way to go. You could get 75w90 gl4 from nissan too, but it still is not as good as the mt90.

mt90 gl4, made the mistake once when younger. With 140wt it wont shift below 35 degrees without double clutching.

I appreciate the replies. I went ahead and ordered the mt90. I was able to get a discount on it too so that's nice haha

Motul 300 for the trans and Shock proof for the rear.

Same here. MT90 FTW!