I have a 98 chevy silverado,it has got to where it skips and i dont know why. it seem to be worse when its cold .I will have it in overdrive and it will start skipping and i will put it in third and it stops skipping .Does anyone have an idea what could be wrong?

Try disconnecting the torque converter. If it is the torque converter this will keep it from skipping but you won't have overdrive

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Im sure someone else has already got back to you on this but i would change fluid and filter and you could also very well have a sensor going bad thats where i would start

The owners manual says to use the overdrive gear under normal conditions and when pulling a trailer.You are suppose to drop down on gears only when going up a incline ( Hill ) that is causing you to accelerate drastically.

put on computer to tell witch selinold

The D inside of an O is for overdrive. It is an automatic overdrive transmission. There isn't an overdrive button on it. If you want to disable the overdrive you have to shift down a gear.

I don't have a a fix for ya but a couple of suggestions.I've found that the OBC's on cars will almost always store a code if any of the electronic controls fail. The fact that you have no check engine light tells me that the failure can only be in the manifold vacuum or fuel delivery system. You may be better able to isolate the problem by monitoring your intake manifold with a gauge mounted in the cab and attached to the intake manifold. Same with fuel pressure. I'm thinking you'll find that the intake vacuum is low and pulsatile, indicative of a blown or corroded head.

belt is old replace-most likely stretched out and brittle the squeal is belt slipping on pulleys also check tensioner for build up

Your O2 sensor is starting to go bad .recomend replacement before it gets worse

I have a 2001 silverado 4.3 and mine did the same thing. turns out the intake manifold gasket was leaking coolant into the oil. try disconnecting the main hose from the radiator and pouring a bottle of bars leak with the pellets in there. it worked great for me has not tapped again.

I had the same exact problem at 175000 miles on my '99 Silverado..after paying the garage several times to read the computer codes to me and ex-plain that 1st I needed an $899.00 head gasket repair, and then just a $250 injector replacement, I decided to run some injector cleaner throguh the system...guess what?............I cetainly am glad I didn't have the head gaskt repaired or the injector replaced...problem fixed