JSolo

iTrader: (14)

I'm out of ideas at this point. Maybe someone else can offer some ideas.

I did notice in your sig that the MY is 2008. Perhaps the 75w95 is exaggerating any syncro wear. Was it as notchy (2-3) before the change? Maybe going back to the stock fluid is the answer. If it was notchy (grinding??) before, and there's still a warranty left, you might be able to persuade the dealer to warranty you a new trans.

In my case, I had this annoying whine present. Ambient temps had to be 20C and above (mid 60'sF), car at operating temperature. Revving over 2K rpm in any gear sounded like there was a supercharger under the hood (mind you, this was on a 2012 from pretty much day 100). Started noticing this after the car was a few months old and ~1500 miles on the odo. We test drove a few others on the lot, all of which exhibited this noise to various degree. At 7K miles I had enough and decided to change the trans fluid (rear end too). At highway speeds, the wind noise overcame this whine and it wasn't as audible.

I still think it might be a good idea to check the level. Who's to say the lift is perfectly level. The redline MT fluid can be had for $12-15 (USD) a qt. It takes just over 3, not sure what the nissan fluid goes for

goredcar

Jsolo... thansk for your suggestions. I will check the fluid and make sure it is totally full. I have had the car since 08 and bought it with 3K miles on it (US car). It always had a slight notchioness on the 2-3 shift and I have heard this is pretty common. I simply pause briefly before going to 3 and have had no grinding. Haven't had any whining issues... glad that you found a resolution to it. I may have some warranty left as I am only at 40K miles and I remember the US warrany being a bit better than in Canada.

iGoya585

Hey everyone, really good info on this thread and awesome DIY BB. I recently changed my fluid using Nissan's MTF. Before changing the fluid I was also experiencing notchy shifts, primarily going into 2nd and sometimes 3rd. Obviously it was a lot more noticeable when the car was cold, but it also happened sometimes even if the car was warm. So I was originally going to go with the Amsoil MTF, but with BB stating he'll was going to switch to Redline's MT85 because of his experience with Amsoil being sluggish when cold. Then after reading mixed reviews about MT85 being a hit or miss, I just decided to stick with the OEM stuff. My main concern was not filling it to the proper level, so as stated I purposely overfilled it slightly and waited for the leaking to stop to indicate the correct fill level. So the first couple miles, it was a complete disappointment (cold shifting notching didn't go away). Finally after a spirited run, that's when I began to feel the difference. So far its been a week, and I feel it's getting better. As far as cold shifts goes, its been better but not what I expected. But when she warms ups, shifts have been butter smooth. Hopefully I continue to see improvements as the fluid wears in. I was definitely excited to see hardly any metal shavings on the drain plug. I added pics, if they don't work I apologize in advance as I'm still kind of new to this forum stuff.

goredcar

I dumped the Amsoil and switched to the GM Friction modified, which is a semi synthetic. Night and day difference... no problem with notchy shifting that I had on the 2-3.

iGoya585

Kind of one of the reasons I was going to go with the MT85. The benefits and piece of mind with a full synthetic fluid is worth it IMO, but it's nowhere to be found (in my area) and I didn't want to wait for it to come in. I was already 10k miles overdue.
Is this the stuff your talking about?
GM (General Motors) - 88900399 - GM Synchromesh Manual Transmission Fluid- Friction Modified

If it doesn't get better before the winter then I might try this stuff out when I take the car out next spring.

goredcar

The stuff you want in in the white bottles... this looks like the right one. I'm not a chemist or a mechanic. I have done a ton of reading on this and the most wisdom I got was from a Honda mexhanic who explained it by saying that a certain amount of friction is necessary for the synchros to work properly... that is why the full synthetics work poorly. Go drive a BMW and see what their tranny's feel like. They are buttery soft, yet move solidly into gear. I know... apples and oranges, but we can get close. The honda guys have been using the GM Friction modified fluid for years.

iGoya585

goredcar thanks for the info. After doing some searching I believe the white and black bottles are they same, they have the same part numbers on them.

Update: Shifting has been smoother especially when the car reaches the proper temps. I've also noticed that shifting before 3k rpm will not notch at all, but overall it's been better (using Nissans 75w85 MTF). I still need to put more miles on it though.

goredcar

I would be a bit careful... in Canada they are different.

The white clearly says friction modified... the black does not

iGoya585

Do you know the "weight" of the gm friction modifier?

JSolo

iTrader: (14)

Be careful with that product (the gm one).

In my old gen 4 camaro, the MT called for a dexron type III fluid. Now mind you, this is the same fluid that goes (went) into their automatics of that era. The only place an additive went was into the rear end, not the MT. My point, nissan calls for a specific type of gear lube for the MT, which is not hydraulic fluid.

goredcar

Check the Acura / Honda forums... those guys have been using the GM Synchro fluid for years and swear by it. I had an Acura CL 6MT and ran the GM fluid for 3 years and it was great, even in winter. The GM Friction modified is not a hydraulic fluid like ATF... I am pretty surprised that GM called for ATF (hydraulic fluid) in a MT.

And... I have no idea what the viscosity is. As long as it gives me smooth shifts I really dont care.

handleandrew

iTrader: (1)

i read this entire thread. there is so much great info on here and it looks really easy to do. I was bleeding my clutch today and figured i'd check my trans fluid for level and color. the manual says the trans fluid should only be "inspected" at 60k mi. so that's what I did (im at 68k mi). I pulled out the top plug to check the level (with car level) and sure enough it slowly started to come out, so I quickly put the plug back in. the fluid looked very clean and light. I feel like this means it is fine and does not need to be changed. is this correct? I haven't had any trans/shifting problems at all. is this fluid like engine oil in that as it wears it becomes darker and thinker or is impossible to tell if your trans fluid needs replacing? to me it seems as thought it is fine but I seek the guidance from a more experienced person. any help is appreciated.

thanks

JSolo

iTrader: (14)

Engine oil gets darker because combustion byproducts contaminate it. The trans is a sealed unit and has no combustion chambers The trans oil is subject to breakdown from sheer forces from the gears.

At 68K you're due for a trans service and rear end if that's never been done.

handleandrew

iTrader: (1)

oh, wow. so is the number of miles the ONLY way to tell if youre due for a change? the service manual just says "inspect" at 60k, so, why not replace (if you know). im not doubting you, just trying to understand. otherwise, what would one be "inspecting"? just the level?

JSolo

iTrader: (14)

That's about it. Given the location it's hard to see the color of the fluid. Not sure where you see 60K either, I see 15K miles for the inspection interval in the maintenance schedule.

For the cost of the fluid ($45 or so, depending what/where it's bought), I just replace mine every 2-3 years. My car is going on 2 years in a few months, and I barely have 12K miles on it. I did initially replace the fluid at about 7K miles because I was trying to get rid of or at least reduce the transmission whine that was audible. The noise wasn't totally eliminated, but did get reduced.