Just took my car to a shop to get some work done and decided to have them service the manual transmission by draining the OEM fluid. This shop does exclusive work on nissan/infiniti cars but after I get home I check the invoice and see:

NEO SYNTHETIC HD RACING FLUID 75W-90

I called this company and found out it is a GL5-GL6 fluid which is warned against using in our transmissions. I called up the guy who works for this company (NEO) the owner actually, and he said I would know within a week if the high sulphur was damaging the brass in my synchros. I have had almost 2,000 miles on the car since the fluid and actually it shifts better than before. I no longer get cold gear grinds going from 1-2.

Since it has been a few weeks and a couple thousand miles and it seems to be shifting smoothly, does that mean this fluid is okay to keep in the car?

I will be getting my rear diff fluid serviced tomorrow so I am wondering if I should just flush the manual fluid with OEM GL4 to be safe or just keep the NEO in there since it is shifting okay?

 

i would change it to the gl 4

probably shifting better cause its a sythetic lube in there right now.

try using amsoil, thats what i put in mine.

TRANNY: http://www.amsoil.com/StoreFront/mtg.aspx

DIFF: http://www.amsoil.com/storefront/svg.aspx

they meet all the specs too

 

how much did that cost?

 

how many miles did you have on your car?

 

I had about 55k when the service was done

guess I will just replace the diff and manual fluid today while I am at the dealer..I just hope there wasn't too much damage done from having it in there for 2k miles...

 

Although the Z calls for a GL-4, there are some GL-5 gear oils that are okay for the transmission. Royal Purple meets GL-5 specification, but is compatible with the brass material in the syncros. You need to find out if the lube you used is true GL-5 and see if it warns against use in transmissions that require GL-4.

 

+1. I use Redline Oil, which is GL-4, so there's no guessing game for me...

 

I just switched to Redline on my last change. Shifting is a little easier but from the looks of it, gas mileage has dropped some.