k well all my friends do this and it looks cool and i really dont think its good for the car, but say they are doin like 60kph they drop it in second from drive and the car gets like a kick forword if u punch the gass. (goes faster then it would in d) should they be doin that? what is the highest speed u should go in second gear.

 

Do you have a tach?
It would depend on what kind of revs you would be pulling.
Also, list mods and anything that might affect engine RPM in a certain gear (ie rear gear ratio), and type of tranny.
Assuming a stock thirdgen V8 in any form, I wouldn't recommend anything higher than the redline (about 5 grand).
We need more info, basically.

 

60 KPH is like 30 MPH. Your car should down shift into second at this speed and pull just the same, if not your TV cable is misadjusted. Is it safe? It does cause more wear on parts but what doesent.

 

Its closer to 40mph, or 37.2mph to be exact. Its not bad, infact the tranny should automatically kick down into a lower gear when you gas it. Its called tranny kick-down.

 

When I bought my new automatic transmission from Pro-Built, I asked Dana (the owner) a very similar question. Being that I drag race, downshifting helps me slow down after a race and doesn't kill my brakes as much. I asked if it's safe to downshift at a high speed, and if it causes any major problems. In short, Dana said that it's OK to do as long as you're giving it gas when you pull the shifter back -- in essence, the same thing as kicking down the accelerator and letting the TV cable perform the downshift. I'd guess that the reason the car lurches forward so much when they do that manually is because they aren't pressing the gas WHEN they downshift, but AFTER they downshift. IMHO, I'd let the tranny downshift when it needs to.