Transmission "Hissing" in gear

[JOEZ33]

Well for a while now I've noticed a slowly increasing hissing sound when put into reverse. The transmission was rebuilt 30K miles ago. It shifts perfectly, and doesn't slip while driving. I just finished a 700 mile round trip towing the pop up camper while the truck was loaded with all our things. After getting home I hear it hissing in both D and R. The fluid/filter is only 1200 miles old.

Also, after starting the engine and then selecting reverse, it takes about 3-4 seconds to engage reverse. If I step on the gas right away then it will roll but it shudders. It only does this in the morning one time, but the rest of the day it goes immediately into reverse. If I park it for an hour or more than it will do it again, but if I don't shut down the engine then reverse works fine.

My personal belief is the hissing sound might be a bad torque converter, and the main pump could be getting weak.

Has anyone seen this problem on your 5r55e?

Thanks

JOE

 

[BrooklynBay]

Did you check the fluid level?

 

[JOEZ33]

Fluid level's been fine each time I check it. No bubbles, not burned, if anything it's slightly higher than the "Full" level.

 

[BrooklynBay]

Connect a 0-300 PSI test gauge onto it to check the hydraulic pressure in all of the gear ranges. There is another port for checking the EPC pressure too.

 

[97sprt4x4]

just throwing this out there. a while ago i had a hissing noise from my car when it was moving. it happened to be the pinnion gear or bearing (not sure which) in my rear differential. not sure if this is what is wrong. but it's a possiblity

 

[BrooklynBay]

Vacuum leaks make a similar sound. The intake gasket is a common problem for leaks.

 

[JOEZ33]

Where can I hook up the 0-300 gauge, and is it a pipe thread or AN fitting?

As for vacuum leaks, it's not that, the sound is very obvious at the transmission, and can't be heard near the engine. The intake gaskets are all new about 2 years ago.

As for pinion noise, its not that either, it does it while your not moving at all. Just hold your foot on the brake and put in gear, once it locks up the clutch pack and you feel it engaged in gear it starts hissing. On my older Pontiac I've had almost the same sound and it was the torque converter going bad. Installed new converter and the sound went away.

If it does happen to be a bad converter, possibly that's also causing a delay of going into gear right after startup? The converter supposedly helps pump fluid besides being a fluid clutch.

 

[BrooklynBay]

Check # 10 in my list of useful threads for more information.

 

[JOEZ33]

I read the #10 post and saw where the pressure port is on your transmission. But on the 5R55E transmission is it in the same place? I haven't looked yet, but I thought there was more than one location that looks the same. I just don't want to get a reading from the wrong place. It also appears that yours has a standard pipe thread so I shouldn't have a problem making a line to hookup a test gauge just as long as I use the right port.