Shift points?

[partsman01]

Anyone have any idea what the speeds are the tranny is supposed to shift at?

It is a 1977 F-250 Super Cab two wheel drive, 400 CI 6.6Litre, C6 tranny.

Just wondering if mine is shifting when it should, also want to try and adjust the band on it too.

[rclarke]

Normal upshifts on a stock C6 will be at 10/12mph first to second and 20/25mph second to third at light throttle.

[partsman01]

Thank you.

[icrman]

There is no normal "constant" speed that any automatic transmission will shift at. It all depends on load on the engine. Its been like that since inception of the auto tranny.
There has to always be throttle position or some kind of engine power output feed back to the transmission control system, if it didn't have that and shifted too soon the engine could be lugged and forced into detonation. This is one of the reasons for an automatic transmission since most people are not engine savy and know how to treat the engine.
Also a reason lots of engines get goofed up, in manual vehicles.

[stuart1]

Normal shifting is considered.

Light throttle pressure.
Even road, no grade.
At sea level.


There is a variation of a few miles per hour to take into consideration other factors.
Load, grade, wind, axle ratio, wheel size all play a significant part.
As does condition of the engine.