Really! If you want to kill your engine, run it hard when cold.

We don't have oil temp gauges on our XJ's like I do on some of my other performance cars and oil temp is the real info about when your engine is fully warmed up and ready to go hard.

It usually takes about 8-10 minutes of driving my "other" car before the oil temp comes up to the normal range while the water temp will be there in a few minutes, depending on outside air temp of course.

This means that the entire block is up to operating temp, not just the coolant.

Just sayin......
Vector

 

Last I looked under, it was rust free. I've never had any work done under the vehicle besides the draining part of an oil change.

As for driving it hard while cold, there are some precarious intersections right out my home that require pep for safe crossing... And catching sequential green lights... Lol. NYC driving is very hard on cars.

The thing with tranny fluid is that I've been previously warned by a mechanic (on a prior car) not to mess with it when it's working, he said sometimes things worn out continue to operate (clutches and such) until you mess with it, and recommended against changing the fluid. Presumably by now the fluid would be saturated with metal-dust from gear wear (140k miles), but after his theory I'm afraid to fool with it. Thoughts?

 

Well, if you're sure that it's the original fluid, me personally I would replace the filter and fill with new fluid. That way you replace only about half of the total system capacity. I don't know the exact amout but, I'm sure it's around that realm.

 

I usually get about 4 quarts out that way, I try to do it three times over the course of a week so I get as much clean fluid in there as possible.

One case of fluid does the job that way.
Vector