No shift on cold tranny?

[6point5]

Hey guys, new here and I've got quite a few questions... to start out with...

When I start up my truck and leave work on a cold day (only let it warm up a couple minutes) and hit the highway I get up to about 3rd gear and it just stays there running about 2500rpm at 55mph til I get about 5 miles down the road when it finally shifts. Is this normal for a cold tranny? When I start it up in the mornings I usually let it warm up about 5 or more minutes and it shifts normally on the way to work. What's causing this?

-Kevin

[Bill Voitel]

Kevin, the computer that runs all of your stuff motor & trans will not let the trans make lock-up until motor is at least 160 deg. Or somewhere close to that. after it's warmed up 190 or so if it has any problem making lock-up (unless your 45mph or less) there might be a bigger issue here. :eek:

[6point5]

Ok, thanks. Hopefully that's all it is. It shifts just fine when it's warmed up.

-Kevin

[FarmerDale]

I have the same problem on my 1995 K3500. This happens rarely, and is usually on a cold (under 40F) start. I happened to be going by a dealership when this happened early on, and there was a code from a sensor that showed inadequate tranny oil pressure to allow the shift to occur. Without fixing the problem, I just shift into neutral, and restart the engine. This resets the computer and things are normal.