Hi there
Have an 05 Dak SLT 4x4 with the 5 speed Auto trans.
Everytime I put the truck into gear I get a strange hissing noise coming from tranny (I think from there anyway). It sounds similar to (I know it is not) the power steering sound when wheels are turned too far one way just without the belt squeal. Sounds like a hydraulic pump when it is pushed to limit.
I just had a tranny service and thought getting both filters changed might stop this sound...it did not. Tranny guy thought it might dissapear as well, since there was a TSB on the spin on filter
There is no slipping or lag in tranny...there are no performance issues at all....shifts like a dream up and down.
Sound is more pronouned when it is first thing in morning and cool. Once the tranny warms up, it almost goes away...but can still hear it.
I don't really want to tell the 'tranny guy' to dig right in to tranny as that gets damn costly for investigating a sound (when it seems to operate just fine).
Anyone else had this hissing noise? or maybe shed some light on it??
Any direction would be helpful.

thanks again

 

Do you have a cold air intake? They will make a hissing sound when you put it in gear when its cold.

If you do not have a cold air intake I would check your intake connections to see if it has come loose. Check the connection at throttle body.

My cold air intake makes a very loud hiss noise when its cold. When I first installed the CAI the engine was still warm. But in the morning I thought I had a trans hiss also. Under further investigation it was the CAI.

 

Good point Eimer.

On a manual transmission however, you should hear nothing more than the gears meshing when you put it in gear. When exactly does it make the noise? When you push in the clutch, when you slide the truck in to first or reverse, or when you let the clutch out? If youre doing all three of those fast and then you hear the hiss, then it could be what Eimer is suggesting. The transmission should make no noise however when the clutch is pushed in or when the gear is selected. If the truck is making the noise when the clutch is pushed in, it could be a flywheel issue.

 

He's got an automatic... : )

 

I couldve sworn he said manual trans! Ah, all these maunal guys bragging on the forum latley has gone to my head. Looks like its time for bed for me. Sorry for my post.

I do hear my auto transmission kick in and in the morning, it sounds like a hydraulic pump. Im guessing normal operation. Is the truck clunking in to drive, or is everything smooth? I would also get under the truck while someone shifts it to see if it is the transmission making the noise.

 

I did install a K&N FIPK.
I will investigate the throttle body.....and at the very least try to record the sound. You would think that that hiss would be there the entire time the engine is running though (would you not?). As soon as it goes into drive .....it is there.....to neutral...gone...reverse...there....park...gone.
I will check it out. thanks

 

Never apologize for trying to help, man! it's all good!

no, the cai hiss's at different times. mine does it too when the ac compressor cuts in....

 

yes...there is a difference! like when youstart it up you'll hear it especially in the morning after its been sitting! and when i put mine in neutral it'll quiet down and then in drive it'll pick up! its all about what kind of load is on the motor!

 

Yea that sounds exactly like the CAI hiss to me. Mine does that same exact thing.

To test it..
On a cold morning pop the hood
Press the parking brake in
Start the truck
walk over to the intake and take a listen
then put the truck in drive (make sure the truck does not move)
walk over to the intake and take a listen

I bet that is the hiss you are hearing.

Mine sounds like it is coming from the trans, but its actually the CAI