Hissing Nosie

[hardcore2001]

The Problem that i'm having on my 01 serria 170k 4.8l is this only started happening when below -10c I have a hissing nosie happening between shift point 1-2 and 2-3 you can also feel it in the shift almost like a hesitation. I have checked the trans fuild level and ever thing is good it only happens for 1 sec at the shift point and goes away after 2 or less min of driving. I try reving the engine in park and also in neutral but it wont make a sound. I'm not to sure if it the same sound or not but right at startup (only when cold) it seem to make a rough nosie don't know if has anything do with it this also is only fort 1sec.

 

 

Great forum

First Post

Thanks

[Nytemare]

Welcome to the forum.

 

I haven't heard anything on my truck like that...or any other one here...but it only gets down to 30* here...maybe 20* if some freak cold snap happens. Having said that...these trucks have some really cool things built into the program for when its cold. One for the trans, it will not shift into third under 35MPH until it gets warm...if the outside temp is below 40*. Chances are its a pressure relief that's being opened until things warm up, that's causing this hiss. If there's something wrong with your trans, you will most likely set a code on the PCM and in turn the Check Engine Light (CEL) will come on.

[hardcore2001]

Thanks for the info