1997 Silverado dually crew cab 2wd 454 4l80e

0411 ecm conversion with efilive tuning

the converter in the truck always felt like an upgraded unit, it flashed to 25-2700 rpm when i get on it but seems to hold fine otherwise, it just never really locked up, even before the 0411 install. its not painted so i dont know if its GM or what. the trans has a GM sticker on it indicating a reman unit but no other history is known.

After about 500 miles of owning the truck i did the transgo hd2 including the pressure relief because i didnt realize it was a no-no. only mods done without trans removal, also did the afl valve since i had a kit on the shelf.
the truck shifts pretty hard most of the time and seems to drive fine but lockup is intermittent though worked for a while. recently it just doesnt lock up so i logged it and it was commanding lockup but the tcc still slipped a lot.
i did some tune tweaks to no avail.
dropped the pan, fluid was nice a dark. removed the relief valve mod and installed the Sonnax TCC regulator valve 34994-01k, no change in behavior.

so.... im sure the converter tcc clutches are now in the fluid.
can i just slam a new converter in? im thinking a hughes xtm

as long as im dropping the trans should i do a rebuild? if so, what should i do while im in there? i dont have any of the old parts i took out when installing the hd2 kit so i need to keep all those mods.

i have some short logs and it doesnt show any slip from TIS to TOS but all the logs were unloaded and light throttle.
I am capable of rebuilding the trans, just dont want to take the days/weeks of the truck being apart to do it if all it needs is a converter.

i disabled lockup in the tune and the truck seems fine driving around

 

if it were mine i'd have to go through it to make sure the TCC circuit is in good order. plus the friction material from the lock up clutch gets everywhere and clogs filters, screen, solenoids etc

 

I agree with truckdoug.
Doesn't sound like you know the history of the trans.
If the fluid was dark then it's probably smoked. Time to yank it and build it.
If you pull it and rebuild it which it sounds like you should, get rid of the 4l80e stock wave plates in the direct and forward drums they tend to break and cause problems. Replace all of the electronics so you're not second guessing problems.
IMO you don't need a wave in the directs (your mileage may vary) only in the forwards otherwise it will engage hard when you put it into gear. Order part #34127 .060" turbo 400 wave. It will never break. You'll have to have different thickness steels to get clearances correct. .090" are #34126A and .077" are #34128. These are Transtar part #s, most places use these.
I've done plenty of the transgo kits with the relief mod because the shops I worked at wanted to. Never had a problem.
Did you replace the TCC solenoid?
Using a know good converter company is worth it's weight in gold IMO. Last thing you want to do is have to pull it again.
Don't forget to flush out cooler lines, radiator, and external cooler if applicable.

 

sorry i missed that this thread got responses until now.
i have not replaced any electronics yet, i have only done the hd2.
sounds like a full rebuild is what i need to plan on, thanks guys.
any other 'mods' i should do while its apart id love to hear about. i built the 4l80 in my ttawd truck but its been a while so im going to have to start over on the learning curve.
thanks

 

just the basic. rollerize the output and dual feed. maybe a line pressure bump if youre feeling spicy.

 

Always start with examining the ATF Level and Health.
Next obtain a Line-Pressure Gauge...
and take reading at an Idle, and at 1,200 to 1,500 RPM in every Gear-Range from Park to Manual-1st.

Some of the OEM/ Stock Torque-Converters would have a relatively high Stall-Speed...
due to the Low-RPM Torque produced by the large displacement of the 454 Engine.
I do not believe that the Stall-Speed was quite as high as you described... but it could be.
The Clutch-Lining in your Torque-Converter is probably finished.

In my opinion, the Transmission is always worth an easy DIY rebuild.
Even though the Truck has had a replacement GM (SRTA) Unit... it is probably old and neglected of Servicing.

The overly firm shifting could be a result of how you installed the TransGo "Shift-Kit"...
or from the PCM seeing slipping via the Torque-Converter not Locking-Up as it should (the PCM increases Line-Pressure in that situation).

You are not going to find too many Builders (High-Performance Builders) that like and/ or use the TransGo Kit for 4L80E Transmissions.
I especially do not like the Separator-Plate and the Pressure-Relief.

TruckDoug mentioned "internally Dual-Feeding" (Free upgrade) and the Torrington-Bearing for the Case to Output-Shaft (very inexpensive upgrade).
Most all units would benefit from a new Pressure-Regulator Boost-Valve and Sleeve.

If you are looking for a new High-Performance Torque-Converter...
Jake of Jake's Performance, builds great Torque-Converters.
He is a Member on this Forum: "JakeShoe"
I recommend contacting him for your 4L80E needs.

 

so i finally got the trans out and got it partway torn down and i think i found out why it ate the converter clutch.
one of the teflon sealing rings on the input shaft was folded over and probably leaked. its the red one in the picture.

 

that'll do it