I got to thinking yesterday - when I needed to zoom Superblue across a boulevard before oncoming traffic reached me - and I hit the “S” button on the shifter to expeditiously do so, how often do other owners actually put their button in that mode? All my Jags that have had S mode – I have always driven them in “R” (regular - or is it “N” for normal?) mode and only VERY rarely put them in S, e.g. when I needed an extra bit of speed for some particular maneuver (btw, I do almost all my driving “in town” and not on the freeways). I also figured that driving in normal/regular mode 99.9999% of the time would cause less wear and tear to the tranny and make it last longer, as well as give better M.P.G. In fact, I have never had a problem with a wear-related issue to one of my trannnys.
So, do you spend more time driving your cat in S mode or regular? Does driving it not in S mode help prolong the life of the transmission?
Timeisrelative
(Jason Miller 1993 XJS 4.0 convertible, 1997 XK8 coupe )
2
I use sport mode from time to time in both my xjs and my xk8. Im kinda old school and kinda think its stupid to even have the option lol. Id rather just have the car have the power/performance all the time, but thats just me lol. I do know that it helps “clean stuff out” to run the engine up in rpm sometimes. My wife has a Jetta tdi, and she drives it back and forth to work at normal driving rpm. When i drive it, i usually put it in sports mode and run it out a little. Theres usually a pretty good line of “coal smoke” behind me for a couple of seconds as the engine gets to blow some of the crap out of it
My cars that had a choice, I always used sport mode. All Sport does is allow the transmission to wait a tad longer before shifting into higher gears, and responds a tad quicker to shifting down to lower gears. You get no more power, you just stay in lower gears a bit longer. I don’t see how it can wear out the transmission any faster, all it’s doing is revving the engine a bit more, using more of it’s torque curve.
IMO, Regular mode is “We want to squeeze out 2mpg more for our marketing”. Sport mode is normal mode - there’s nothing sporty about it.
My 94 XJ12 with the GM 4L80E has the same function as does my GMC utility van with the 4L80E. It just keeps the transmission in lower gears longer. My GMC van weighs in at about 8,000 pounds and loaded is probably 12,000 pounds . This lets one know how sturdy the 4L80E is. The other Jaguar transmissions with this feature functions the same. Keeping it in Sport mode will lesson your fuel economy. One thing a person can do to lengthen transmission life is to keep the selector set below the overdrive gear setting. When you are coasting the transmission tends to shift to the overdrive gear and back and forth when driving below 40 miles per hour. This strains the overdrive gears and they have a tendency to fail early when driven in city driving for extended periods.
In fact, I have never had a problem with a wear-related issue to one of my trannnys. 
