crusty

Correct, mostly. The early V8 did have the 3.54 ratio. Once the V8 got the 7-speed they all got the 3.36. Go aback in history when the Titan was launched with this 5-speed transmission. Nissan claimed the 3.36 ratio was like others 4.10 ratio. The logic/math was the 5-speed had a much lower 1st gear. So the standing start was very close. But the Nissan 5-speed overdrive ratio was also very different as well. The normal 4-speed transmissions that were out at the time had 0.70-0.75 overdrive. While the Nissan had only .85 overdrive. If you wanted to play even more, the Titan XD diesel has a 3.92 ratio in the same axle design that can be swapped into the Van's axle. Or a 4.09 in the '20-24 Titan XD with the 9-speed (has a really tall set of overdrive ratios). Nothing wrong with running in 3rd gear. The VQ motor likes some RPM. It has an oil cooler. The basic engine design goes back to the mid 90s. Versions of this engine are used in Z-cars, an alphabet soup infinity cars, well regarded in the engine design. Trying to change the axle ratio is going to still put the engine into the same RPM band, just in a different gear, and make driving without the trailer much worse.

Not a chance of the 7-speed bolting up. The back of the block is completely different. And the programming of the transmission is completely wrong as well. The V6 is OK in a mid sized truck. Not really a good choice in a full size van that is trying to tow. It can move it, just not a great job of doing it as you have found.

Was just watching Hoovie's Garage. They are fixing a Hellcat. The entire engine build is on hold because they can't get a set of rings. Something that should be easy to get on a late model hemi. The cam was scarce and had to pay extra for one of the few that could be found. Parts are just hard to get.

Not just these vans. Every vehicle is having these issues. Trying to remember the part, but a co-worker was quoted a 14-month backorder for some common part. I think it was a chevy. Insurance is totaling fairly minor damage vehicles simply because they can't get the parts to fix them.

Just got mine. Not installed yet. See how it goes for me.

You are correct. Like every production car I have ever seen the speedometer gets input from the rotational speed of the wheel, driveshaft, etc. There is a calibration in that speedometer based on the rolling distance the tire will cover per revolution. In the olden days you could go in and get a different gear (different number of teeth) to correct for different tire sizes as well as different axle ratios. That was the driveshaft based speed. Modern stuff runs wheel speed sensors. That feeds an RPM signal into the ABS system. The ABS knows how many revolutions the tire turns per mile, and a little basic math will give speed. There is another speed sensor for the output shaft of the transmission. That feed back to the transmission so it can monitor that the gear ratios are correct and the transmission isn't slipping. Just like the old transmission speedometer days but this has no gear. It is done with software. Fun bit, if you change axle ratios and the cruise is on, you can get an engine code for something like mismatch of speeds that will keep the cruise control from working until you turn it off and start it back up again. I don't know of any real good way to correct a speedometer for oversize tires in the vans. A cheat sheet (or stand alone GPS speedometer) is the easy way to really know.

Also idling the engine will be heating the van. Hot engine under the hood, blowing hot air under the chassis warming the floor, not to mention the added heat radiating off the exhaust. You would be adding to the AC load. Idling engines are not very efficient either.

There are 2 very different styles of fan clutch. What year and what engine are you working on?

ECM is under the hood BCM is under the dash. If you heard a pop, it probably wasn't from inside the ECM under the hood. I would guess BCM behind the dash. The other thing that makes pop noises is when fuses blow. And Nissan likes to put fuses all over the place. No old days of one fuse panel. Some under the dash, some under the hood. Don't expect to find just one fuse to the module, several fuses for different operations.

What codes are in the computer? Computer failures are pretty rare. The typical hard start, long crank, is bad crank/cam sensors. Happens out of the blue. But that is only a guess. Pull codes before going down the rabbit hole throwing bad parts after good.

Getting time for a new battery. Can't find solid information of what the factory size is. All the parts store look up guides list multiple sizes, some are drastically different. From what I can tell, I have the bigger factory 27F. Just wondering if there is a bigger battery that will fit without modification? Not going to modify anything. I know that if I am willing to change battery cables, make new hold downs, etc. I can stuff just about anything in there. Not doing that. Just the biggest drop in is all I am after. Only worried about the BCI number at the moment, I can shop around for which brand once I find if there is anything larger than stock.

It's programmed into the ECM

Watch clearance to the brake calipers. Pretty sure the rear brakes have less clearance than the fronts. I pulled the overload leaf out and installed airbags to get the height down to squeeze into my old garage. New house got the 8' garage door option and is no longer an issue. I've also known people who have had the garage door header raised. Smaller tire will start playing with overall effective gearing, speedometer, odometer, etc. 3" too tall to fit a garage means 6" of tire height. I don't see how you are going to get that to work.

To what you have said, it has worked for you for the past 3 years. That is it worked for you. For someone thinking about copying this idea, think about yourself and not just what worked for one person. There are parts of the country that are not so gentle. Where I live, I could probably get away with it. I have friends who live places where you watch metals oxidize faster than paint dries.

No rules, put in what you want.