My 6MT vs Auto driving impression. Opinions please

wstar

I've been driving mine in manual mode since I bought it. Just about to flip the 30K miles mark, and no issues so far. Maybe 20 miles of that tops have been in D-mode, rest all manual shifting. It gets a track weekend about every 6-8 weeks lately, too.

I did do a full fluid swap at about 20K, which is also about the point I installed an aftermarket transmission cooler (small Setrab core), because the 7AT does get a little bit "mushy" and slow if you let the fluid overheat from an extended session of aggressive/track driving. The tiny Setrab core that Stillen uses in their kit was enough to fix that up (I didn't use their hoses and fittings though).

While that's all positive, I don't have any illusions about its longevity. Ultimately, it's still an automatic transmission, and internal clutches will wear out, etc. I imagine at some point, long before the 6MT would eventually die somehow, the 7AT will need a rebuild. I don't think anyone's put enough hard miles on it to find out when that is. My rough guess for planning purposes right now is that I'll make it to at least 60K even with all the track days before it starts becoming an issue. Maybe longer if I'm lucky. I'm sure they rate it for ~100K, but probably not with me driving .

As for torque, the unit is rated for a considerable margin over the stock engine's torque output. It's rated for 295 ft-lbs, which is more than enough to account for bolt-on mods. Once you start getting into FI territory though, you're exceeding the design's torque limits, and you'll probably burn it up faster. GTM makes some internals upgrades to help with that.

The mfg (Jatco) also makes an alternate version of the same transmission which is used in the 7AT SUVs from Infiniti/Nissan, and is rated for 442 ft/lbs. I still think swapping one of those in might be the best option for FI, but I don't think anyone's seriously tried that method.

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