I am planning on changing the MT fluid with a Mobil 1 75W90... in the hopes of reducing/eliminating the synchro whining.

Those of you who have gotten the fluid change done - did it help with the synchro whines at all?

I am thinking about doing the rear diff at the same time with Lucas heavy duty 80W90 (o.e. spec) gear oil. Domestic guys swear by this product and I am willing to give it a try, yet curious to see if anybody else has used it. The Lucas bottle specifically notes "excellent for LSD."

 

the whining i am addressing is when you are 'coasting'; letting off the throttle on any gear, any speed and voila! ~~~~~weeeeing weeeing weeeing. ugh. i just turn up the sucky bose or just leave my foot on the throttle with 5-10% pressure and it goes away.

i've pretty much come to a conclusion that the transmission/clutch in the Z is a noisy one (put the car in neutral and let the clutch out... woah!) so i am just trying to reduce the noise a bit.

 

I got that annoying a$Z whine too. so its the throttle body?

 

Mobil 1 75W-90 gear lube is GL-5 and not suitable for our MT. This was confirmed via phone between one of our members and Mobil techs just a few days ago.
Please read the "Changing the differential/ transmission oil" thread that is currently active.

 

I have a slight whine when in 6th on the freeway above 70mph when just bearly on the skinny. Is this the whine you guys are talking about?

 

^^ yeah probably. Same whine here. Goes away if you add or take out the throttle, but only present when maintaining constant speed.

 

Yep, I got that. Is that "normal"?

 

hey z'd. thanx for the info. i SO read that thread and it totally went over my head; i dont think i was paying attention.

i still want to try the lucas heavy duty gear oil for the differential, as its readily available and supposed to be real good. i want to use stuff that are readily available, yet recognized as the "good stuff". what are my options on the MT fluid that are readily available? other than the oe nissan fluid.

 

You have a couple of options- look in your yellow pages under oil /lubricants for Amsoil to locate a local dealer- I am sure there are some around. You want their gear lube designated "MTG". That is definitely 'good stuff'.
Or, you can visit your local auto parts store and check out their selection of gear lubes with GL-4 rating and pick the best name brand available. Hopefully they have a good brand in stock.