I have a '94 Q45 and I have towed a small boat. I have Tokico struts and have added a rear sway bar and the biggest problem is that it pulls so well that you have a tendency to forget what's out back. Now about the transmission. I installed a trans temp gage and found readings that were alarmingly high when towing in summer. Pretty high when not towing as well. I then did a fluid change to Mobil 1 synthetic and dropped temps more than 10 degrees! Best thing an owner can do for transmission longevity. I also added a large trans cooler which I located in the spot for the Q45A suspension fluid cooler. (Between of the drivers side front wheel and the fog light. The splash guard in the wheel well is already ventilated.) This cooler dropped my temps significantly. I have only exceeded 200 degrees on a couple of occasions in traffic and brutal heat. The transmission has been totally reliable as has the rest of the car. A further note about towing. Most boats are set up poorly on their trailers. This car cannot handle much tongue weight. Spend time and adjust the boat and trailer until everything works. It's time well spent.
I have a 95 Q45, and when I bought it in 2003 it already had over 96K. I moved the following year from LV to NYC, and towed a medium-size, fully loaded U-Haul trailer from Nevada to New York. No Tranny cooler, but I did drive at night only, and chose the route with the least inclines. At some times I completely forgot I had this big box in the back, and found myself in the left lane passing traffic at 85mph. This car just hauls.
OK, that's the good news. The bad news is that recently the transmission started to drip. I tried all those liquid sealers, and they worked only until I stepped hard on the gas while passing, and then again drip, drip, drip. I go through about a quart of tranny fluid every 200 miles, and that's not good. Of course I should have it fixed, but to be honest I'm afraid of what it'll cost. A guy in the neighborhood spent $2500 getting his transmission rebuilt, and I just don't think it's worth it. As long as it doesn't get any worse I'll just keep puring in the Penzoil.
This week I started to hear a kind of rubbing, brushing sound from the front left wheel-well. I suspect the shocks are going. Can anyone confirm or perhaps offer another diagnosis?
Towing anything with a Infiniti Sedan V8 is highly not recommended because the rear subframe is mounted on silicon filled bushings.
Get a truck or a cheap pickup, or a Titan or Armada with a separte frame if you must tow.
Probably it is just a matter of who has been using these cars before they got into our hands. Mine is a 93 Q45 with a 360,000 clicks on it, and I am towing 17 footer liner without an issue.
Like the others said, you sometimes forget that you are hauling something behind you. With that much power underneath your foot, it feels like more than 300 horse power, It's so amazing!
But no matter how credible and powerful a vehicle is, if it was not taken care of by you nor the previous owners, somebody is going to sacrifice their dollars for a costly repair.