[Overhead]

I have a 2004 denali 6.0 and the flipping transmission slips between 1st and 2nd and 3rd when cold and only under light throttle. If I use a heavy foot it doesn't slip at all even when cold.
A 15 minuter run and the tranny warms up with no slipping at all even under light throttle.
The oil is clean and clear with no smell at all and I change the filter every spring.
I hate the thoughts of taking it in to the mechanic since it's always a rebuild and never just fix the problem for a reasonable price.
I am an aircraft mechanic and can easily fix this thing with some decent input of what i'm looking at or for !
What a pain !!!!

[bigblockragtop]

A 2004 has an onboard computer so maybe you can take it to a place like autozone to read trouble codes first, they do it as a free service . Sorry really just a guess but hope it helps

[gonzo08383]

have a trans shop check ur line pressure when its cold. could be a bad valve in the pump. sounds like a pressure related problem. get it checked out sooner than later, those trannys have been burning up 3-4 clutch packs since they were 700r4's!

[Crosley]

Overhead.. Welcome to Hotrodders.com

I edited the thread title to provide the membership information on your problem. This also helps the ''search feature'' on the board