One more tranny fluid question for unDummy.

[aquariuscsm]

In my everpresent quest for my manual transmission refill,Royal Purple Max Gear 75W90 states GL4 and GL5. It also contains limited slip additives.........would this create any havoc? I`m considering either the Royal Purple Max Gear or just going to the dealership and grabbing some of the Genuine Nissan Manual Transmission Fluid.

Those two look like the ones that are readily available in town. The Nissan fluid is $9 and the RP is $11.

Whatcha think unDummy?

 

[aquariuscsm]

Also,since I`m getting the 1st to 2nd grind once again,is it just time to call up Nissan Consumer Affairs and ask them what`s the deal??????? I have to literally accelerate in 1st,let the RPM`s completely drop,push in the clutch,shift from 1st to neutral,then from neutral into 2nd to avoid the grind. I have the MY350Z.COM forum pulled right now and you wouldn`t believe how many 350Z owners are having the exact same problem as me. Some of their cars with the grinding transmissions are as new as 2007 models.

 

[aquariuscsm]

Oh,I forgot to mention,it shifts the absolute smoothest on a cold first-of-the morning drive,especially when the outside temperature is cold.

 

[Titan]

Wow. Sounds like the OEM fluid is too thin. It's ok cold, but, as it heats up at all, it begins the grind-thing. Better wait for an expert, though...and that's not me!

 

[kd5byb]

I'd vote for a thicker fluid, if your best shift is when it's absolutely cold and the weather is cold.

Have you tried the Amsoil MTG? It was too thick for my wife's Lancer, which called for 75W-90 gear oil, causing hard cold shifts.

later,
b

 

[aquariuscsm]

Titan and kd5byb,I`ve been thinking the exact same thing (hence unDummy also wanting to hunt me down and kill me for mentioning thin ATFs and synchromesh fluids,heehee!).

I`ve been Googling transmission fluid and gear oils all night since I got home from work. I think I`m going to try RP Max Gear 75W90. It meets the OEM specs and the experts on TT.NET have had the best results in their cars with it. I emailed RP and they recommended it as well.

 

[unDummy]

LSD additives could create havoc. Usually gear oils with it don't have a full dose and still work OK. But, I wouldn't bother with the RP.

Because every transmission is different, it truly depends on 'each individuals' feel with a fluid. I've seen 2 identical transmissions prefer different fluids. You'll have to experiment with the various brands. And, you'll have to run the fluid twice(rinse run/final run) before drawing a conclusion. Since you are ALREADY filled with Nissan 75w85, you SHOULD use it one more time before switching brands.

Sounds like the transmission has something expanding causing a bind that leads to the grind. I would highly doubt that the numerous z-problems are caused by fluid viscosity, since just about every weight/type has been used over the years. It is definitely a manufacturer issue.

Another thing to do is experiment with fluid level. A very perfect cold shift on a 'cold-dry' transmission is interesting. Could it be that the transmission fluid has dripped down overnight and it takes a few minutes for the splash lubrication effect to work into the unit???? Test this theory during your next service. Drain a hot pint out and run it around the block to see if a lower level(less splash) helps. Then see how it shifts with the cold correct level immediately after refilling.

 

[aquariuscsm]

Well,after doing a ton of research here and on a few other sites,I`m going to swing by the Nissan dealer and buy 3 quarts of the Nissan MTF and see how it works out. I`m afraid to try any other brand since the transmission`s under warranty.

 

[cheetahdriver]

if the z's are anything like the miata's (the 1-2 crunch sounds identical) the tolerance spread on the transmissions is so big that what is the silver bullet for one is sand in the syncros for another. i finally tried Molakule's MT fluid (no longer available, durn it) and after it had time to scrape the EP additive off the syncros, it works really well.

note that it took about 2k miles to get to the "really well" point. i assume it was the EP additive that had to wear off, but i am not sure.

i also really get to gloat because i got some of his P/S fluid, which made the miata steering better than either of the porsche's i have had lately (and thats really setting the bar too low for the improvement i got).

i have to agree with unDummy though, keep trying different stuff until you hit one you like (or you get rid of the car). if there was a general silver bullet the z forums would be all over it like a cheap suit.

 

[aquariuscsm]

I had a guy from one of the 300ZX forums email me last night who had the exact same problems.........brand new manual transmission that would grind 1st to 2nd gear unless he shifted VERY slow (1st to neutral,then down to idle,then into 2nd).

Well,he thought he`d give it a fluid change to see if it helps. When the fluid drained out,a small clip came out with the fluid. A spring retaining clip that activated the synchro,thus the synchro not doing its job.

The transmission has a year/12,000 mile warranty,so I`m just going to keep on going and see if it progresses.