I know of someone with an auto Z that also has his tranny go before he hit 20k miles

It's not really a sealed unit. It has drain and fill plugs (much like the rear diff), it just doesn't have an easy-access dipstick/fill tube, and the service manual doesn't state any maintenance interval on their chart that goes to 60K miles (and claims it's "maintenance free").

Also, the procedure for refreshing the fluid in the service manual is a pain in the *** process of repeating: partial drain, partial refill, warm up the transmission and shift through the gears, shut it off, repeat again x3-4 times. And for the final accurate fill level, you have to get the transmission warmed up to a very specific temperature for the fill hole's level to be accurate (and of course, the trans fluid temp isn't available via "normal" OBD-II diagnostics, only Nissan's proprietary Consult tool at the dealership).

I don't trust their "maintenance free" crap though. I've made it just a hair under 20K miles so far on my factory fill (well, + 1/2 qt or so that was added recently as part of installing the trans cooler). The small amount of fluid I spilled out of the lines while installing the cooler looked pretty fugly though, and so I do plan to replace all of the fluid soon now. I'll probably take it to a dealer here (Baker) for them to do their filling procedure.

The big question mark to me right now, is whether I stick with Nissan's Matic-S fluid, or switch to Redline D-4 (the only quality aftermarket one I've seen that actually claims Matic-S compatibility).

mmmmmmm

:tup: this

"Maintenance Free" and "Sealed Unit" also applies to BMW autos. But as a previous owner of one, I wouldn't have gotten too far by following those guidelines.

They will need to have their fluids replaced at some point if you plan to keep the car for a long time.

cc370s experience is a little scary, so I'm not going to borrow trouble; I think I'll use the paddles occasionally. I think a tranny should last longer than the engine and this car has to last at least 10 years. I don't see any downside to changing the tranny fluid at 36K but that's a long way off.

Thanks for all of your inputs!

Charles

the is nothing wrong with changing the fluid at whatever interval you want...

BUT...

if you have even the slightest inkling that a transmission problem may be happening in some way, shape or form, don't change the fluid, consult a transmission specialist first. It is VERY common for transmission fluid changes to exacerbate transmission problems, especially in automatics, not so much manuals.

Other than that, change away!

I'm not sure what the issue is with cc370s, but I don't think it's because he used the paddle shifters. I use mine constantly and no problems to 20K so far. has the dealership given you any diagnosis on what went wrong with the first one cc370s?

My experience with every car I've ever known of (mine, friends', etc) has been that automatic transmissions in general are one of the most failure-prone big-ticket items on any car. They're just extremely complex, and they do contain lots of internal wear items. Based on my past experiences, I think expecting any auto trans to live 10 years without some kind of service/rebuild is expecting too much. But then again, most of my experience is with older transmissions too. Perhaps these newer generation ones will be more sturdy for the long haul.

Still, a manual is going to outlast an automatic by a lot. It's just so much simpler mechanically.

You're probably right. I have two Maximas, a 95 and a 96. The 95 needed a tranny rebuild at 109K. The 96 is still going strong at 130K (I'm estimating that one since the odometer broke at 86K). In the case of the '96, the transmission is more reliable than the odometer!

Wow, that fluid replacement procedure sounds hellacious. I doubt I'll let Jiffy Lube do it. :-) Frankly, I don't understand the "maintenance free" issue either. You change every other fluid in the car and I think the transmission gets as stressed as the engine, though there's obviously no combustion involved. Still it gets very hot and must be subject to wear.

If you always drive in M there is more wear on the 2 magnetic torque converter sport clutches "less slip mode" .
Changinging the Oil is never bad, depending on drive style. The Gearbox is designed also for the 5 Liter Infiniti V8 with higher torque, so maybe this is the reason for the infinite transmission oil change interveal. I dont belive in that. You can always see the wear of the 7 planetary gears and the break bands in the automatic oil pan. So you can see what driver was on the car if you have there a lot of metall wear in the pan. The service manual says exchange the gearbox if you can find some one millimeter metalic peaces in the oil cooler of the gearbox. :-) This is the right idom " Where wood is chopped, splinters must fall"
On older automatic gear boxes you can adjust the gear break bands. You cant find anything in the service manual..so its a exchange gearbox if it is not self adjusting.
Also there are rumours that the turbo mods do not hold the torque with the smaler 6th and 7th gear diametor planetary gear brake bands.
Thats only my opinion

Actually, this is a myth. There are two versions of our 7AT made by Jatco, one is a lower torque rating and one has a higher torque rating. Our cars get the lower torque version, and Nissan/Infiniti SUVs get the higher torque version. Most of the details I dug up on this are over in this thread, starting around here: http://www.the370z.com/forced-induct...ml#post1151774

28000 km at least 100 pass down the drag strip 4.08 gears shift as 7500 to 7800 rpm, no issiues yet.
changed the fluid when i did the converter. too 3 tries to fill it , siimple to do it just takes time

So you made more investigations to find out whats concerning about torque at our 370z AT. :tiphat: But this is concerning only the fluid converter for the V8, am i right ?
I do not think that jatco is doing a redesing of the gear box.. so a more heavy non highspeed car has a different acceleration "speed" converter thats located bevore the gear box...maybe they do also something with the differential rear (awd behind the gearbox) ratio to handle it.. your are right .. i didnt thought about that :tiphat:

ZeeYouLater

This is not a rumor but ANOTHER MYTH being put forth by 6MT guys on this forum. NO ONE has blown a tranny OR HAD PROBLEMS with the tall gears on the 7AT except shumby. Truth be told......NO ONE KNOWS exactly why his tranny failed. We (FI 7AT guys) suspect the "clutches" between the tall gears are not strong enough to handle the torque (so most of us had line pressures increased in the tranny to keep clutch time between shifts to a minimum).

I will end this with a question......I have had 2 track days, 30 or so runs in the 1/4 and 1/8th mile, 4000+ miles of VERY SPIRITED driving with 500 rwhp.........Why havent I had any problems?

P.S. The truth is most of you nay sayers are working off hearsay like chuck05 above saying "I know a guy whos auto tranny didnt last 20k miles" and believing it without any proof or substantiation at all. Shumby is the ONE AND ONLY that is a proven failure.

P.S.S. Please dont bring up the thailand guy.....no one ever really figured out what he was saying happened.

P.S.S.S. Why is the rumor "turbo mods"??? Shumby in an SC guy???