: 4T80E Viscous Torque Converter Internals / Clutch Failure (Lots of pictures included)



maeng9981
12-09-11, 02:31 AM
First off, I'm sorry but this is not a typical P0741 ask/reply thread. If you need help with your P0741 issue, please read this thread (http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/103217-torque-converter-clutch-p0741-tcc-stuck.html) or you can search for other threads.

Some of you might remember my recent thread regarding a supercharger-like whining noise coming from the transmission. Shortly after I noticed that the TCC wasn't engaging as it should, and then P0741 popped up (with no SES light?). But I thought "a failed torque converter should not make whining noise?". Well I decided to give the transmission a fluid change, but I found lots of metal debris inside the oil pan and I knew there was a bad future waiting for me.

Here's the debris I found - A LOT:
http://i.imgur.com/n1vuq.jpg

Of course, not so long after the "Supercharger whine? (http://www.cadillacforums.com/forums/cadillac-seville-cadillac-eldorado-forum/240805-supercharger-whine.html)" thread was made, the transmission gave up running and I was again in the situation for a cradle drop.


http://www.youtube.com/watch?v=eZiZ8kKKGAY

Well, with funny adventures, today I finally put the transmission back on the engine. I really had no idea how to take the torque converter bolts off using the service area with my limited tools, so I took the starter out and used the hole to remove the bolts. (The part of the reason why I love the unique design of Northstars). That worked quite better than expected.

In the meantime, I scored a used Y transmission with 34k on it, out of a 2000 Deville, for $300. The business owner said he bought the business with the transmission on the shelf and it hasn't been sold so he's selling it for cheap. He said he is not sure about the mileage but he has seen the donor car (already stripped down); he said it wasn't involved in a crash. Oh well, I went ahead and purchased the transmission. Later I went to the nearest dealership to purchase a TCC PWM solenoid and asked for the info of the donor car using that GM database (former VIS). They said they can't pull up any personal info but they told me that the last service record from GM was 29k miles and it was in 2008. So the 34k sounds about right.

http://i.imgur.com/iBbVG.jpg

So the used transmission was put; and then I have a failed transmission and the torque converter sitting on the garage floor. What do I do with those? I always wondered how these torque converters work and what is inside, so I decided to open the old one up. It was already throwing P0741 so I knew it was no good. I believe this is not a factory torque converter; or it's serviced/remanufactured before. I don't think any factory torque converters came in teal color.

After lots of sparks flying around, it was cut in half. The left is the transmission side (input shaft area) and the right is the flexplate(engine) side:
http://i.imgur.com/87xap.jpg

Here's the stator and the bearing:
http://i.imgur.com/p9iZb.jpg
http://i.imgur.com/AyVis.jpg

Here's the turbine inside the converter which now shows the viscous torque converter clutch:
http://i.imgur.com/LnN0K.jpg

And then the viscous torque converter clutch:
http://i.imgur.com/r8H8P.jpg

Doesn't it look a little dirty? Well I thought this was the metal bits that flew off when I was cutting it in half. Indeed some of those were from the process of grinding metal. Well I decided to pull it out and found...

http://i.imgur.com/HvX2m.jpg
http://i.imgur.com/B20kn.jpg

The bottom full of clutch material! No wonder the whole transmission was full of clutch material.

I decided to flip the viscous torque converter and found something very interesting. It looks like there should be 4 bolt-like fasteners to block the 4 holes shown below:

http://i.imgur.com/iFpAv.jpg

There were only two of these blocking the 4 holes and the clutch was apparently leaking trans fluid-like fluid through the holes. And these don't look perfect either; both looked like it was grinding against the housing. The head is gone, and I could turn them with my fingers:
http://i.imgur.com/Vyro7.jpg
http://i.imgur.com/rM670.jpg

If you read my previous thread you might notice that I was wondering what kind of viscous fluid that the clutch actually uses. I heard it was "silicone fluid" but had no proof. The reason why I was wondering this was that I found clear sticky fluid on the "secret" drain bolt. If the silicone fluid was indeed used, then there was a possibility that the seal of the torque converter has failed (now apparently) and was leaking internal fluid everywhere.

It looked like the clutch pack was sealed pretty well and it looked like there is no easy access so I decided to cut a little bit:
http://i.imgur.com/VIaOt.jpg
http://i.imgur.com/TtD7Z.jpg

maeng9981
12-09-11, 02:34 AM
Inside, I found the exact same clear fluid I found on the "secret" drain bolt! What a surprise? :)

So basically the inside of my original transmission was full of crap - mixture of clutch material, viscous clutch fluid, and the transmission fluid. No wonder why it produced a whine. I don't think the fluid pump will run well with all those crap running inside the transmission. I have yet to open up the transmission, but I am pretty sure the source of the noise was one of the fluid pumps.

A question arises; what did cause all this mess? A leaking torque converter clutch? Lots of clutch material? Or it was just a buggered up torque converter installed by someone? I found no transmission service records other than PCM reprogramming related to transmission back in 2001. Is it even OK to drive with P0741? I certainly wouldn't want that kind of fluid with that viscosity running inside the transmission.

What a bad luck, when I first bought the Seville I really wished I could run this car until the body parts fall apart - and I thought that would be far away from now. Well, the head gasket failed and now the transmission is replaced with one from another Cadillac. This time I just wish I DON'T have to drop the cradle of this car, never again!

---------- Post added at 01:34 AM ---------- Previous post was at 01:31 AM ----------

Here are more random pictures I took during mating the engine/transmission.

http://i.imgur.com/2HUs9.jpg
http://i.imgur.com/AmbbD.jpg
http://i.imgur.com/PjsCj.jpgp
http://i.imgur.com/VigPV.jpg

vincentm
12-09-11, 10:44 AM
After all this, i bet you love your Cadillac even more now! It has taught you alot about it, it's like it was waiting for you to purchase it, knowing you'd take care of it.

M5eater
12-09-11, 10:56 AM
This thread deserves a golf clap, I love it when people tear apart stuff :)

*golf clap*

mtflight
12-09-11, 05:59 PM
I hope someone here will know why the TCC is teal and hopefully can understand how this happened. Kudos to Harry for his DIY spirit and abilities. Very impressive!

iflipcars
12-09-11, 09:12 PM
I worked in a few repair shops over the years, and one was a very busy transmission shop. All of our torque converters were a teal color. They were supplied by a company that remanufactures them. They picked up all the cores upon delivery. I'm assuming that paint just gives em a better look and longer shelf life. I never thought twice about it, but it does appear that the quality of the remanufacture on your unit is seriously lacking.

Ranger
12-10-11, 12:20 AM
WOW! Hell of a job. :bows:


Is it even OK to drive with P0741?
I get that code with some regularity know. No problems and I just dropped than pan and did a fluid change last summer. I found nothing like you did.

maeng9981
12-10-11, 02:07 AM
After all this, i bet you love your Cadillac even more now! It has taught you alot about it, it's like it was waiting for you to purchase it, knowing you'd take care of it.

Yes. I honestly don't think I could've learned this kind of stuff if the car didn't break down. The only thing I haven't done is the block bottom half reseal, but I am going to learn & perform that for my Deville.

This car sort of popped up. It was about two years ago, I wasn't even going to get a Seville, I was looking for a newer Deville but this car sort of popped up from somewhere and I felt like I had to buy it.



This thread deserves a golf clap, I love it when people tear apart stuff :)

*golf clap*

I was cutting this torque converter like a crazy person thinking "you screwed up my transmission!"


I hope someone here will know why the TCC is teal and hopefully can understand how this happened. Kudos to Harry for his DIY spirit and abilities. Very impressive!

When I am done with the repairs, we are going for a lunch to celebrate, my treat. Finally we will be representing white diamond Cadillacs at parking lot H.


I worked in a few repair shops over the years, and one was a very busy transmission shop. All of our torque converters were a teal color. They were supplied by a company that remanufactures them. They picked up all the cores upon delivery. I'm assuming that paint just gives em a better look and longer shelf life. I never thought twice about it, but it does appear that the quality of the remanufacture on your unit is seriously lacking.

Yeah, the more and more I look for info on torque converters, the more and more I believe that this has been remanufactured. I found that the original color of this failed torque converter was the same color with the one that came with the used transmission which looks factory. It does give them a better look since the color of the factory one matches with the flexplate and it's not a good color. (But who care about something that is hidden 99% of the time??) So yeah, to me it looks like the quality of this (remanufactured) unit was very inferior to the factory one.


WOW! Hell of a job. :bows:


I get that code with some regularity know. No problems and I just dropped than pan and did a fluid change last summer. I found nothing like you did.

I hope it causes no more trouble for you. For me, now, it looks like the quality of the reman'd torque converter was questionable and it led to the complete transmission failure. The whole clutch has literarily worn out internally and externally.

mtflight
12-12-11, 11:57 AM
I ran across this post today, and find it appropriate to link to it here as reference for future cybernauts.

http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/149834-information-p0741-p1860-1998-a.html