automatic transmission wont change

I got a 1999 chevrolet silverado 4x4 and when it is cold [around 30 degrees or lower] after the truck is warmed up and you start to drive it will change gears one time but it will not get above 30mph until it warms the transmission I guess, but inside the truck the heater is warm. So do anyone know whats wrong?

I know that with a cold engine my truck does not shift as it does when warmed. I believe GM has intentionally programmed trucks to shift like that until the engine reaches a correct operating temperature. It might be something to do with fuel milage? I read it somewhere... just forgot the details.

My '99 Silvey does the same thing. I don't think there's anything wrong. GM has the system programmed that way I believe. There might even be something in the owners manual about it, I think.

It's in the manual for 2003 , dont worry

Unusual shift patern to aid warm up.
Below 30* in the AM , sometimes takes 2 or 3 miles to shift all the way up.
I just take it easy for the first few miles.

From page 2-23 of the owner's manual --

"On cold days, approximately 32 F (0 C) or colder, your transmission is designed to shift differently until the engine reaches normal operating temperature. This is intended to improve heater performance."



From page 3-6 of the owner's manual --
"On cold days, approximately 32 F (-0 C) or lower, if your vehicle is equipped with an automatic transmission, you may experience differences in how the transmission shifts until the engine is warm. This feature automatically reduces the time it takes for the engine to reach normal operating temperature and shortens the time it takes the heater to reach full output."

regards,
Leon

I guess this question is related, I´ve driven cars with manual transmissions all my life, this chevy is my first automatic (I am now too lazy to go back to manual) but anyway, If I select 2nd gear going down a very very steep hill, when I reach the bottom and make a full stop, if I leave the selector in second gear, it really struggles to get going up the hill again, so I have to move the shifter to 1st gear myself and only then will the truck shift into first gear, is this normal? I thought that if you put it in 2nd gear, it would only shift to 2nd, but still be able to shift down to first gear :confused:

These will start in 2nd if you leave in 2nd. One other thing I just might add...Brakes are cheaper then transmissions. So be easy on the manual shifting unless you really need the engine braking to help stop.

I hear you, but sometimes when I go to the mountains on dirt roads and I´m going down hill for 5 7 even 10 minutes and there is no guardrail, with a straight drop on one side of the road and the cliff on the other, with the road following the contours of the mountain, you can glaze and overheat the brakes pretty quickly. Some people that live there have even installed water sparyers in the wheels to cool down the brakes, ´cause you´ll start getting that burning smell pretty quick, once you overheat you´ll loose all braking power, so you HAVE to go down in low gear tapping on the brakes for a couple of seconds all the way down to keep your revs down, you wouldn´t believe all the trucks totalled in the bottom of the cliff next to the river due to brakes overheating. One guy that hauls machinery up these hills even installed an extra water tank on the top of the cabin, he has a manual tranny and when he goes up the mountain, he begins to drain the radiator and fills it with water from this tank, otherwise the engine WILL overheat before he reaches the top. fun ain´t it? :naughty: As a side note, the first time I went there I found drops of sweat getting the steering wheel all wet.

silveradoman, you must take pics of this place. I'd love to see it.

I have some pictures back in my parents house, I´ll try and get them up here. In the meantime, this picture might give you an idea. This one I borrowed from www.mexicodesconocido.com.mx. Mine are not from the tourist trap part of it, but it´s pretty close to what I got to see.

http://files.automotiveforums.com/gallery/watermark.php?file=/500/222846barrancas_del_cobre_3.jpg
http://www.cercosalamo.com/coppmap.jpg

I'd use the transmission too lol