4th and 5th gear not kicking in when cold

[paraordnance]

Was driving to work this morning and its brutally cold outside. -32 C (-25 F) or -43 C (-45 F) with a windchill. I warmed up truck for about 15 min. Coolant temperature was still going up when I left home. I have about 15 min drive with up to 56 mph speed and I believe transmission was still in 3rd gear or about 2200 rpm. Normally it would run in 5th (1600 rpm) on the same stretch of road. I manually shifted into 4th and rpm lowered to 1900-2000 or so, when I shift to D it goes back to 3rd. Is this normal? I seen this behavior several times and its always happens when cold (below -20 C). Some kind of defence mechanism to warm up tranny?

 

[riverider]

I think it's the system computer keeping in the lower gears till the system knows the engine has warmed up enough to shift into higher gears.

 

[Mike07SE]

This is common in computer controlled trannies these days. Trans will hold lower gears a lot longer in order to get the fluid temps up to specs as quickly as possible.

 

[brucemoose2]

That's what engineers call "by design".