New manual tranny fluid fill question.

[aquariuscsm]

I`m getting ready to put a brand new updated,beefier manual transmission in my Z (it`s what Nissan calls a 98+ spec OEM manual transmission). Does the factory-filled fluid need to be changed at a certain interval (a break-in period per se)? If so,what`s the best possible stuff to use (for synchro protection/bearing protection,and best shiftability)?

That particular manual transmission requires a GL4 fluid only. I`m replacing my car`s current transmission due to synchro/bearing failure.

 

[bmwtechguy]

If it requires a GL-4, the Redline and Amsoil fluids work well. For GL-5 protection, the Redline 75W-90NS is usually recommended for a synchronized manual trans.

 

[mechtech2]

I'd change it out at 5,000 miles or so.
Sure, you can go longer. It's just that it should have a decent break in at this point, and you'll flush out the accumulated particulate matter. You won't regret it.
Specialty Formulations is my first choice, but they are not shipping for a while.
I'd go with the new Amsoil in the appropriate viscosity/grade.

 

[unDummy]

I definitely dump the dealer fill ASAP. Sorry, but without knowing what bulk oil they use, its not work risking a new transmission on generic GL5 gear oil.

For the best protection, use a non-LSD GL5 gear oil. Examples are the Redline 75w90NS, Synlube, and Motul Gear 300.

For the best shifting, use the Redline MT90 or Amsoil MTG. These are both excellent GL4 75w90 fluids.

Since you're in Texas, I'll assume that winters are short and not too cold. If so, you can try a Mack T0-A Plus SAE50 gear oil. An example would be Mobil Delvac Synthetic Transmision Fluid 50 or Schaeffers 742.

 

[aquariuscsm]

I believe Nissan uses a conventional Pennzoil GL4 85W90 gear oil as factory fill. I`ve been leaning toward Amsoil. Would that be better than just draining and refilling with the OEM Pennzoil?

 

[bmwtechguy]

I would use the Amsoil MTG 75W90 GL4. It should shift better for longer betweeen service, and shift better when cold such as first few shifts in the mornings. Also, most likely won't cost much more than the OEM fluid, which is usually overpriced for what you get.