Big call .... I have been involved in competetive motorsport for 40 years, raced 500cc motorcycles in the 70's and sports cars for the last 30 years.

I have 70,000klms on my Z34 and I have a problem with 6th gear syncro. Started after the 5th track day and the root cause I believe is transmission oil temperature related - it may be exacerbated by a lack of mechanical sympathy over time, but I can only report my experience which is that in my car, it is now possible to consistently "beat the syncro" on a skip-shift from 3rd gear and max rpm into 6th .... unless I wait for syncro-rev to sync the rpms, I can consistently beat the syncro's. Even 5th to 6th need to deliberately slow-paced (not condusive to a good lap time I know, but just another problem to drive around).

I agree - for one owner to have had 3 transmissions, there may be an element of lack of mechanical sympathy involved .... especially if the clutch driven plate was "fused to the flywheel" - sounds like the vehicle is subjected to arduous service, but don;t accuse the guy of not being able to drive - he may simply have a different definition of what Mr Nissan's transmission product should be able to tolerate.

I have a 6-speed straight cut gear and dog-engagament box in my race car (from Holinger Engineering - they do boxes for 996 GT3 RSR, the M3 GTS and up until this year supplied the V8Supercar control transmission), and given its level of engineering, I still strip it every 3 seasons (5000 race klms) to crack test the gears, replace bearings, dogs and oil pump bits because in that time it will have been subjected to ~160 race starts and around 2-3000 flat shifts.

Now if the originator of the thread beleives Mr Nissan;s transmission ought to tolerate that level of work, then maybe his (or her?) expectations are never going to be met, but I think accusing him (or her) of not knowing how to drive may not be the most positive point made on the thread .....

Like I said, it culd simply be a case of different expectations ... the NISMO Race Car comes with the same gearbox in the roadie, and NISMO "lifes" the box at 5000klm. So if a box is subjected to race-type service demands in a roadie, them maybe 3 transmissions is actually a predictable outcome as the "in service" requirement is outside what Mr Nissans designers have catered for.

All I know is that the OEM transmission in my car is exhibiting signs of syncro wear after 70000klms and that for me is a sign of arduous service (it has done a lrge number of track days) .... I'm now fiddling with oils to see if I can get some more mileage out of the box before I pull it out. If I do pull it out, I'll have the think about what it gets replaced with.

Making a statement like "3 transmissions = don;t know how to drive" is not logical - there are lots of other reasons behind "why".

BTW - if you read the signature - the car is a TT, so the box is being asked possibly to tolerate torque loads beyond its design limits - most TT kits that run more than 4-5psi boost are going to put at least 50% increased torque demand on the transmission ..... and if the guy is running more boost, the problem wil be worse .....

Hehe who knows about the extra power involved. It tops off at 380 ft-lbs right now. For daily driving it doesn't see much more than 2 PSI during the week. I'm pretty sure if my engine is taking a fair bit of abuse then my engine would have popped by now (knock on wood).

The original had to do with an issue with the aftermarket disk having too much marcel. It felt like the disk was constantly rubbing on the flywheel making it difficult to shift. Of course none of us realized that until the first day at the drag strip that I barely got out of the hole in 1st when things got worse. We pretty much attribute it to overheating from the 1hr wait in line with the stop and go traffic. Several times I had issues getting in gear.

The first replacement was fine, but I barely had it for a month when I had issues getting in 5th. It wasn't notchy. Half the time it took more effort going in, but never grinded. It got worse the next couple months which is when my tech tested it and decided on the replacement.

He doesn't think it was built quite right.

Just because I'm running turbos doesn't mean I abuse this car. It is my only vehicle and it is a daily driver. I pretty much baby this car. There are others running boost and drive it like it's stolen with no problems whereas I'm driving it to work on the freeway everyday. The only time I took it to the strip was when the clutch failed, and it has been 8 years. The 350z only been to the strip once.

[EDIT] Got word about my 3 month old transmission. Hopefully I can get a hold of it for synchro upgrades.

My '09 6MT Base model transmission was recently replaced (warranty) due to a bad 5th gear grind - the new box shifts very well, and schnucks right into gear quickly. However, I also noticed a new whine in 2nd gear. Perhaps this is just a result of beefing up some parts.

--ZOM

Do you notice the part number is the same? Either that or inconsistent build quality.

The receipt shows only 1 part number - not sure if it's the new one or the one that was replaced:
320B0-1EA0A

--ZOM

So it lasted 3 years in stock form and 4 months after you put in the new fluids and clutch and HD CSC? Sounds like keeping a stock trans and fluid in there would be the best right??

No direct correlation. 5th was tough getting in after a month. I tried redline for a few weeks before the tech decided to get the transmission replaced. Shift effort was great, but 5th wasn't getting anny easier. It snags every other time. My current one is running redline since it was installed. It is doing well so far.

You're an idiot...




for those of u thinking this is "driver error" u are mistaken. i have never owned an automatic car in my life. heck i have a manual volvo running twice the boost as its set at from the factory, it has 165,xxx miles on it. it has the stock trans, STOCK CLUTCH, and has never ever had a probelm with either. mind u, that is a car with about 310lb ft of tq. had an 87 944S with 200k on the clock and NEVR had a trans problem even after going thru 2 clutches. 25 year old car... 200,000 hard miles... rwd...

now, i have had the z for about a year and a half. bout the car with 15,XXX miles on it. at about 20,000 miles the 5th gear synchros starts to go. trans has to be replaced. so either i completely cant drive a manual for 5000 miles, or the z's synchros have a problem.

Also, it SHOULD NOT MATTER if u skip a gear on a transmission. been doing it for 80,000 miles in my volvo and that trans is as smooth as butter (even after some abuse). still fine to this day. synchros do not know which gear u came from... all they do is match rpm speed. a synchro does not see a gear coming and go "mother of good... that thing is spinning 500 rpm faster! i can't handle this!". also, a synchro doesn't have anything to do with tq or hp levels. it simply matches rpm speed. so tt or sc should (theoratically) not cause synchro failure. but clearly there is something wrong with the design of the synchros.

its amazing how people have been skipping from 3rd to 5th since the invention of the 5 speed transmission yet every trans in the world hasn't need replacing.... yet when it happens on a z it "is a driver error". c'mon now. its well documented that we have synchro problems.

I lost second gear today, woot! just under 20k. 5th gear syncro would grind when cold as well. MAN DOWN. I know the guys at the local dealer so hopefully they do not give my any crap because I have a SouthBend clutch and CSC, if so, a fight they will have! This trans has always been clunky from the time I got it, nissan could never get their manual right or CVT or...

Agreed. No CVT. For awhile I'd see a car getting a new CVT whenever I went in for an oil change. This included the new pathfinder.

trans is ordered, should have the car back next week.

Nissan sent me a letter "upgrading" the warranty on my '09 Maxima's CVT to 100,000 miles. Nice. I haven't had a bit of trouble with it though. Maybe they're actually improving...

One of the advisors I work with is a former Nissan service manager.... you have done well on your cvt, I hope we do not jinx it! Still waiting for mine, what suck worse is I live 1/4 from the dealer and drive past everday, still sitting there haha. Honda is switching to CVTs, I cant wait to start dealing with these breaking.

My sister has an '07 Versa with a CVT. 114k miles and no issues yet. Also had the rear brakes finally replaced at 98k miles. Fronts are still original. Not trying to give Nissan too many brownie points but the one my sister got sure is a keeper.

On the topic of a manual tranny, maybe someone should point them to Honda for advice. Good idea, Tigger! Write Nissan corporate a letter. I will! ;)

You know how many 3rd gear sets we put in civic si tranny's...ill help you, A LOT hahaha.