Has anyone used synthetic oil for manual gear box? Does it help smoother shifts?

My 2004 shifting is horrible (grinding) during cold starts (7 out of 10 times) and even during warmed up conditions (3 out of 10 times). Does anyone think using synthetic oil will help improve shifting performance?

Thanks for any help,

2004 Sedan 6mt, Blk on Blk, Nav, Prem, Sports, Aero, Sat

 

take it to the dealer. they will replace your tranny for you for free and you will LIKE the new one. if you put synthetic in there you will void warranty on the tranny.

the tranny should not grind ever. a little notchy when cold is ok and normal. audible grind is totally unacceptable. I have had mine replace twice because of grindage. Each time was better and smoother. this one is SO much better, 3rd and 5th are really close. 6th gear is a whole lot easier now: from ANY gear.

1-2 is still a little rough at redline but no AUDIBLE grind

Sean

Better Life thru Chemistry
Black on Black 03.5 Sedan 6MT - Goodyear F1 GS-D3's 225/55/17, Custom Intake Tube, '03 "Z" Suspension, Magnaflow resonator, 6 Wire 4 Guage Grounding Kit

 

I put Amsoil synthetic in my '03 350Z. It improved the shifting dramatically. I also put synthetic diff fluid in the car too. Synthetic will NOT void your warranty as long as the specifications are in line with regular fluid.

 

Many Thanks for the feedback.

I am not sure if there is audible grinding during shifts (like as if shifting was tried without fully depressing the cluth?). But it is certainly notchy in almost all shifts (1-2, 2-3 etc.,) sometimes even when the car is warm.

During cold start, there are times when i just cannot shift to second from first even with full force, after two or three attempts and with the cars behind frowning, i give up and shift directly to third. Man, no offense, but i loved the Honda gear shifts.

I will take it to the dealer, but i can already hear him say, 'oh we could not duplicate the problem' it just makes me sick.

 

yes, the dealer can void your warranty if you use synthetic. this has happened to several 350z guys already. i don't know if Infiniti will be easier to work with than Nissan, I doubt it. Infiniti may reverse the dealer's decision when you mention the Magnuson act but do you want to go thru the headaches?

you can fight it but the problems go away with the new tranny, 2-3 is a straight shot, you can feel the gates, but there is almost no resistance. go test drive a 2004, that is what it will feel like.

You sound like you have enough probs already. get the tranny swapped. it will fix all your probs, plus the clutch has been upgraded. the clutch grabs a whole lot better.

yes synthetic will make the shifts better do a search for "shell manual transmission fluid" on my350z.com. but it is gonna be 40 or 50 bucks for something you can have for free.

a tip from my last test drive with the service manager. make sure the tranny is very warm (drive 30-40 miles before the they test drive it). When the fluid is moderately warmed it actually lubricates better and isolates the "feel" of the shifts better. you can feel problems in the shifter better hot. drive to the dealer in a gear lower than you normally would. they almost could not duplicate my 5-6 grind in the "cold' tranny.



Better Life thru Chemistry
Black on Black 03.5 Sedan 6MT - Goodyear F1 GS-D3's 225/55/17, Custom Intake Tube, '03 "Z" Suspension, Magnaflow resonator, 6 Wire 4 Guage Grounding Kit

 

vtz, what if anything did you notice after doing the diff oil change? I'm considering changing both diff and tranny fluid next time I'm in for a service... was gonna do redline on both counts, but I'm interested in hearing your experience.

Jase aka Doogie
04 G35S

 

3point5SE-Auto:

I think you meant for him to go test drive a 2005, not a 2004 - I have a 2004 6MT, and it grinds 1st to 2nd, 2nd to 3rd is not smooth but very "notchy" and the gate is balky, and I grind every time when shifting quickly from 5th to 6th, even at 3,000 RPM. This tranny has always been notchy and balky, sometimes "locking out" 5th & 6th, requiring me to go back to 4th, then try again.

I'm gonna test drive a 2005, to see the difference myself. I haven't told my dealer about my MT problems yet - waiting for them to get worse (and therefore undeniable by the Service Techs), and also to get a new one that is completely updated and correct. I don't want to be posting how I've had my tranny replaced 3 times, like some people here have done.

My $0.02

Sport Sedan Fan - 2004 6MT Sedan
Sport/Navigation/Premium/Aero; "Invisiguard" Bra, Madico Onyx Tint
Obsidian Black/Graphite & "Titanium"
SHE'S SILVER & BLACK - GO RAIDERS!

 

Dbarnes, I believe you are right. I have a 2004 too and 3.5SEAuto probably meant a 2004.5 if the tranny is as good as he has described it. I am meeting the dealer this week or next, i will keep the group posted on their feedback.

Prabhacar

 

I immediately noticed an ease in shifting. I have never experienced grinding or any problems before or after the synthetic. Even in the cold climate here in Vermont. I would highly recommend synthetic.

 

vtz,
I don't mean to detract from your advice. that was my first thought when I had problems the first time. I have had another vehicle do this to me and synthetic fixed it wonderfully to make my shifts silky smooth. but if you research it more, Infiniti will put a new tranny and clutch in even if you have 70k miles on your drivetrain. IF YOU CAN PROVE THE GRIND.

Yes the tranny is as smooth as I describe. You can feel every gate and notch, but the shifter just slides into place. You know how on the 2-3 shift you go up and to the right? When I shift leisurely and don't go in a straight line. I can rest my hand on top of the shifter and move it into third by just waving my hand across the top of the shifter towards third gear.

Better Life thru Chemistry
Black on Black 03.5 Sedan 6MT - Goodyear F1 GS-D3's 225/55/17, Custom Intake Tube, '03 "Z" Suspension, Magnaflow resonator, 6 Wire 4 Guage Grounding Kit