Who really knows what the answer is? A lot of theories out there. One thing I do know is that on most cars with overdrive, it's recommended to drive with overdrive turned off in city driving because of the wear and tear on the transmission. My theory is the less gear changes the tranny is doing, the less wear and tear on it IMHO.

We have a LOT of hills here in Portland, OR so I like to use 3rd around town, and sometimes 2nd (and even 1st when the traffic is heavy) so I don't have to ride the brakes all the time. It does make it more snappy too! I figure that if that wears out the tranny, it'll start showing soon enough to get it taken care of before the warranty is up- unless a bonafide mechanic with actual knowledge on the affects on this tranny comes out with the facts

 

Hmmm, good idea. Any mechanics out there care to weigh in on this? Which is worse on your tranny, higher sustained gear speeds or frequent shifting?

 

Im not a certified ' mechanic ', but ive worked on my own cars for the better part of 40 years. My personal opinion is the less shifting it does, the longer its going to last. During the shift process is when 95% of the wear occurs. Engines and transmissions both can take higher RPMs with no problems. Its that slipping going from one gear to the next that will eventually kill them. Its like slipping the clutch on a standard trans, and it kills the clutch, usually sooner than later.

 

I drive a commercial vehicle (2004 model) with a diesel engine and an Allison 5-Spd. automatic transmission with electronic push button controls. In stop and go driving you can bump it down and lock it in third (or whatever gear you need) . It helps control your stops with much less brake use and eliminates the tranny from constantly searching up and down. Vehicle has transmission temp gauge which seems to indicate it runs cooler when you are not shifting up and down. Makes sense as each shift under power causes some friction in the clutches which in turn builds heat. Torquing up on the brakes even in large vehicle builds heat quickly also. This has mode control also which when you engage with a push of the button lowers your shift point on full throttle upshifts(which I am always doing)from 2700 to 2300 which you can override by locking it in each gear and manually using buttons to upshift. They recommend using the lock in gear for stoplight to stoplight instead of leaving it in 5th or drive?? I always like big vehicles because you can wind through gears and run full throttle without penalties. Still get big noise and turbo whine just without the drag race feel. You would be amazed how many drag races you can do with other large vehicles in a 100 mile city driving day. Still a thrill to put them down without worry about cops!!!
PIGMAN