Caution, the following is an exercise in speech to text so I apologize if the AI got it wrong

Hello gentlemen, hope everyone’s having a great evening. The transmission in my truck went out or is on the way out. This was the first Transmission I ever built and has given me great service up until yesterday and today. So yesterday after installing a new engine, I was doing some data logging and noticed the temps were up about 20° from the usual 140s to hovering in the 160s, after about 20 miles of driving, I decided to turn around and when coming to a stop, I could feel it downshift and it stalled coming to a stop. I started back up and then it stalled again going from part to drive. Part in reverse would do the same thing , then all of a sudden it went in gear fine and I was able to drive home without further incident except for slightly elevated temperatures, which finally reached and stabilized at 171°. Today I went on a 40 mile round-trip and about 18 miles in it started dropping out of overdrive When coasting downhill. Give it throttle or go back uphill and overdrive would reengage. I pulled out my computer and hooked up the data log because I thought maybe the torque converter clutch was unlocking, but that was not the case. The computer was commanding fourth gear, but it was clearly downshifting . After about 10 more miles, it started dropping out of third gear and would stay in second I could command full line pressure and torque converter lock up and it would stay in second gear and sometimes up shift to third and then drop back out again after a little while this , it gave me full neutrals. No gears no drive but it was coasting at 40 miles an hour with no throttle and would coast and slowly slow down. Any amount of throttle felt like neutral. Put the selector into third or D3 since I have the sonic HD valve That gave me gears back and I could have first and second with torque converter lock up commanded occasionally it would upshift a third and come right back out again. I drove 45 miles an hour all the way back home gear and torque converter lock up worked fine when I reach home it tries to shut off again , coming to a stop so I put it in neutral and close to my parking spot and turn it off. The highest temperature was 183° the ground and I couldn’t smell anything but I know we have a catastrophic failure of some sort so tell me what you guys think , have a great evening

 

IMO you have had a converter clutch failure, the stalling is the hint . Probably just started stopping everything up, then eventually broke through pump screen and really clogged things.

 

ya know, I had that same thought. I’ll bet you are right. The only other thing I could think was that the 3-4 clutch was welding itself and breaking apart again or the 2-4 band was getting stuck on but the tcc deal makes a lot more sense. I’ll keep you up to date. Thank you.

 

Well, as it turns out, I believe it was converter failure of some kind. The clutches actually showed very little where. Even the 3–4 clutches, even though there was a bad shift flare temporarily, and then they completely gave up the ghost so to speak. I believe now what happened was a complete and utter loss of line pressure, due to the clogging of the main filter, the little screen in the pump was clogged and blown out. The stater now has a series of rings around it just outside the lip seal. The inside of the pump has the tail tail rings they give away inclusions of some kind , but it is very minor and the rest of the pump, including the bushes shows barely anywhere at all It’s amazing you do all you can and still you have a complete failure

 

Just had a similar with a customer and a brand name converter , Didn't make it a couple miles. They sent trans back all was perfect but all clogged with converter clutch. Screen blown out in pump all screens clogged. I cleaned all up an sent back they got new converter all good now but costly for all.
On the plus side since pump did take some scarring was my first time doing a complete machining of the pump face and back along with pocket and went well so can do that stuff now .
I always try and find an upside .

 

That is true. Could you do this with a brake lathe? I don't have any machine tools yet. Im sure I could find a brake lathe though.

 

NO. A brake lathe leaves too rough of a surface.
I've seen it attempted (6L80), and it looked like ****.

 

It can be done with a brake lathe. Back in 90-91, we had a builder that would reface the pumps, I remember him doing 700s and 2004r but I'm sure he tried to save as many as possible.

 

Not sure on a brake lathe never tried would need a super slow fine cut, This is what I use Works well, Getting the slight center off set on front half for center worked out was a little tricky but after that works great super slick cut

The big trick is slow and fine, Took about 45 minutes to get both sides done as a I wanted of course that includes setting up and some figuring out, Have only done 2 so far but came out nice, Of course WIT sells the back for 75 done with new stator so its questionable if it is actually worth the trouble to do . But cool to be able too. I may start facing at least both sides as one thing I noted (THEY ARE NOT STRAIGHT and surely leak alot ) I marked this face and the first cut only .005 hit and missed large portions of the back. The second cut though cleaned it up at a .005 final . Only issue with my lathe is no auto cross feed but will make variable PWM motor drive for it later when im caught up a bit. Haven't run ads in months and they just keep coming. But slow steady hand does fine too.
Lathe is also awesome as I like the TG PR VALVE but wanted orings and never liked how fine the Sonnax orings are so easy to tear so cut a wider slightly deeper groove in the TG steel valve and thicker orings way better and test sealed solid with air at 175 psi .
Assuredly facing and the orringed Boost valve cuts back on leaks massely IMO . Trick with just doing pump face and not pocket though is making sure pocket still deep enough for slide so does not get stuck, Two solutions possible here, If pocket good then optionally you can machine the slide, Or they do make various thickness slides but man those are hard to get not much if any assortment available from suppliers. But sorry for the off topic rant, As for a brake lathe was looking at some in photos and I would say yes some of them could as some are pretty fancy with variable speeds and cross feeds . But would depend on the lathe.