I was accidentally shipped the wrong tranny fluid. I thought I had ordered Amsoil Series 2000 75w90 (GL2 - GL5 compatibility), but was sent Amsoil's Severe Gear (specifically rated GL-5). Now, to my understanding, the 350Z is specifically rated for GL-4? I've read that GL-5 causes premature synchro wear? Also, I noticed that the Amsoil Severe Gear 75w90 is not even recommended on Amsoil's 'Application Guide'. What do you all think I should do with this stuff? Put the Severe Gear 75w90 in, or put it away and order the Series 2000 75w90?

 

Our cars use 75w85, any other oil will void the warranty.
The cars doesn't use 75w80 or 80w90.
75w85 is a special GL-4 for manual transmissions, only available from Nissan. I believe some of the Dodge trucks use it in their transmissions, and Dodge dealers also have it on the shelf.

 

Just to add to the confusion, the Nissan service manual dated May 2003, Revision Oct. 2003, states the following recommendations:

Genuine Nissan Manual Transmission Fluid (MTF) HQ Multi 75W-85 or API GL-4, Viscosity 75W-85 or 75W-90.

That's verbatim.

I do know that my other service manual (dated Dec 2002) stated only the 75W-85 API GL-4. When I went to the dealer and asked for the 350Z tranny oil, they handed me a bottle of Penzoil 75W-90, which I did not purchase.

For what it's worth, I switched to Amsoil Series 2000 75W-90. Although it did not cure the third gear grind (when cold), the tranny is so much quieter now.

I went systhetic in the diff also and it feels like I can break the tires loose much easier now.

 

I wouldn't use a GL-5 oil in the manual transmssion. GL-5 has a higher concentration of extreme-pressure additives, which can corrode the syncronizers. Stick with with a GL-4 unless you know for certain that your GL-5 is designed for compatiblity with yellow metals.
Mika

 

For what it is worth I use Royal Purple Max 75W90 and it most definately is compatible with all yellow metal requirements.

I have used it fro 5k miles and it most definately resolved a 1st to second "crunch" under very rapid speed shifts with a rougue shifter. I used to crunch about 1 out of ~20 shifts before , since the change out , never had a crunch since.

The only downside noted so far is that for a few miles after a bone cold start, downshifting into 2nd takes more effort (the second grear sychro produces less useable friction when cold).