Automatic Transmission - Self Built 4L60E (on my 95 LT-1 Vette) Squeals for 5 minutes on Startup

Rebuilt 6 months ago....

changed out rebuilt pump and reopened case and checked and reinstalled all about 5 1/2 months ago.

Tranny works fine.

Only problem is I have a high pitched chirp/squeal that modulates on and off then gets just a little more constant before it stops about 5 minutes after startup.

Happens hot or cold but only after the car sits for a couple of hours.

Have had the pan down numerous times...no metal and fluid is nice and clean.

There was some minor steel dust on the magnet in the pan.

Also, tends to do it more in gear, but also quiets down somewhat out of gear.

Seems to put the engine under a little load at idle when it squeaks, but I may be wrong.

Started doing this not too long after new pump was installed due to clearance and pressure problems in previous rebuilt pump.

I figure I'm not digging back in until either it starts squealing like a crazed pig or it just blows up :)

Any thoughts on what it could be?

I would have to think that the noise is coming out of the pump or the converter. I had a customer with a TCI converter that was doing the same thing. The bad thing is that it took the pump with it and the transmission did not have a good clutch left in it by the time he decided to pull it. Vince

Wow, if you are thinking that the engine is under a load when the squeeling is apparent, then I would think something is chewing itself up pretty good. I would not recommend running it until it suffers a significant failure unless you intend on replacing the unit outright or completely rebuilding it again. Sometimes transmission failures are local, meaning a hub broke, a snap ring failed etc..... but more often than not the entire unit suffers when it goes down.

Have you checked the fluid condition since this began? I would be interested to know what debris is in the pan.

g

Re-read my post, pan info is included :)

I would have to think that the noise is coming out of the pump or the converter. I had a customer with a TCI converter that was doing the same thing. The bad thing is that it took the pump with it and the transmission did not have a good clutch left in it by the time he decided to pull it. Vince

Pro-torque converter was rebuilt for rebuild.

13 Vane Pump was rebuilt by me (new GM front cover) and was perfect when installed......

I also had posted rebuild photos on this site :)

Oh well, thought this would get a little more input than that:eyes::D

Oh well, thought this would get a little more input than that:eyes::D

Hi sorry I know we have disscused it before but still dont know where to steer ya, Wish I could hear the sound maybe that would help, Perhaps a video with sound?

Doh,,, I knew that. I did read that in your comments... just didn't think about your pan comments when I was typing my thoughts out.

Well..... here is what I would do myself if I was faced with this job in my shop.

Initially I would determine if indeed the noise was coming from the tranny, probably is but I would verify it by unbolting the converter from the flexplate, sliding the converter into the pump making absolutely sure it was not going to interfer with the flexplate and I would then start the engine. If the noise is still there then we know it's in the engine.

But we are pretty sure the noise will be gone though, right? Right.

I would then turn the engine off and rotate the converter very carefully by hand before removing the tranny, the goal would be to see if there is a high spot or in other words a spot in the rotation where it seems to bind. Also, I would look to see if it rotated "true", looking for a bent hub on the converter. Knowing that it is warm by now it might not be as apparent as if it were at ambient temp. Next I would remove the transmission.

From there I would very diligently inspect the converter hub and front pump bushing for an abnormal wear pattern. If nothing obvious is found I would remove the pump for disassembly and inspection. From there, while it was apart I would inspect all surfaces that have a facing bearing or bushing for abnormal wear marks.

Not sure if that is going to get you where you need to be, but that is what I would do.

Hope that helps you out.

g

I'm going to first see if I can get a video recording of the noise and post it:engarde:

Well Happy New Year All :D This is on my 95 LT-1 Black Corvette Coupe....

Just wanted to finish my story...sorry, didn't do the vdeo I promised :eyes:

So about 6 weeks ago it started getting more quiet...remember, it only squeeled for about 5 minutes on startup......

About two weeks ago it totally stopped making any noise, works great...I drive it daily to Manhattan 46 miles each way.

Fluid smells and looks like new with no metal on the dipstick :D

Runs a cool average 150F at 40F ambient with my B&M cooler.

Only one little problem still exists. After parking overnight, it leaks a little fluid from between the pump and case, not the TC shaft seal.......I've taken off the cover while on my lift and observed this visually. Have tried cleaning with carb cleaner and gooping up between pump body and case of tranny, it helps, but won't totally cure it. BTW, I had changed the pump to case side rubber seal with a new one when I pulled the tranny the second time to replace the pump :confused:

Oh well, guess I should be satisfied that it works great otherwise.....:angel:

Well its good to hear your noise went away. A common place for the type leak you have is the pump bolt orings