Transmission intermittently disengaging after torque converter change.

[Charles Vella]

I have a 16 silverado 1500 5.3 6l80 that started to shutter so I replaced the torque converter. After doing this I replaced the fluid with ac delco dex 6 and ensured the fluid was at the right level. I drove the care for 5-8 miles to test it, the next day I pulled out of my driveway and the vehicle was bucking and not engaging the transmission as if it did not have fluid. I checked the dip stick and it was at the correct level, I then dropped the pan and noticed the a lot of black sediment at the bottom of the pan(no shavings or big metal chips). The filter appeared to be clogged, so i changed the fluid and filter and then was able to drive around 40 miles before this happened again. Does this sound like a i need to rinse and repeat this process until the sediment that was jostled free during the converter swap is gone or is my transmission done for?

[Snowcamo]

Time for a rebuild. Contrary to popular belief this happens more then will be admitted. Changing the fluid is a death sentence for the transmission with decent milage.

 

Over the years I have gathered the detergent of the new fluid cleans and washes away the sediment that is within the clutch packs. While that sounds cool its actually counter productive as that very grit came from the clutch packs and aids in grip.

 

I'm sure others will say otherwise, but let this be a lesson for future reference. Don't change the fluid.

Edited June 1, 2022 by Snowcamo

[newdude]

Converter failure always takes out more than the converter.  Most take at least the pump housings, many wipe out clutches and the TECHM.

 

Needed to come more apart to see what else failed to begin with.  

Edited June 1, 2022 by newdude

[Snowcamo]

2 hours ago, Charles Vella said:

I have a 16 silverado 1500 5.3 6l80 that started to shutter so I replaced the torque converter. After doing this I replaced the fluid with ac delco dex 6 and ensured the fluid was at the right level. I drove the care for 5-8 miles to test it, the next day I pulled out of my driveway and the vehicle was bucking and not engaging the transmission as if it did not have fluid. I checked the dip stick and it was at the correct level, I then dropped the pan and noticed the a lot of black sediment at the bottom of the pan(no shavings or big metal chips). The filter appeared to be clogged, so i changed the fluid and filter and then was able to drive around 40 miles before this happened again. Does this sound like a i need to rinse and repeat this process until the sediment that was jostled free during the converter swap is gone or is my transmission done for?

Did you fill to converter before installing?

[Charles Vella]

19 minutes ago, Snowcamo said:

Did you fill to converter before installing?

Yes, refilled as much as i could. I spun the tq and rocked it and jostled it to ensure the fluid would make it all around the tq before installing. I replaced the input shaft oring as well.

[Snowcamo]

Ok. Well here's to a successful long lasting rebuild. Look into sonnax for upgrade parts kit. They are the solution to these transmissions. 

 

Note these transmissions have pressure issues. Most try to bump the line pressure up via tune and that's cool, but is not the proper solve. 

 

In your case you noticed shuttering. That shows a lower the required fluid pressure issue somewhere. 

 

May you be blessed.

Edited June 1, 2022 by Snowcamo

[WT35002017]

I’m not an expert. I finally received a stall converter that I ordered about 2 months ago but I won’t have time to replace mine for another couple months.  I’m very interested in not having my linings self destruct before I can replace the converter but I wasn’t able to change the lockup programming on the TCM until about 2 months ago with HP Tuners. The stock programming is part of the problem with these trucks. It allows for slip all the time for a smoother ride but it prematurely can and will wear the lockup surface which then pollutes the transmission. If you were driving fine and you suddenly lost forward or reverse gears, it could be the plastic balls in your valve body getting stuck in the the holes. I believe Sonnax makes a rebuild kit for valve body and they also make stronger parts for the rest of the transmission. If I were dealing with it I would pull the tranny and inspect all clutch packs and clean the whole thing out. Look at the pump first of course as that will be tell tale of what’s deeper in but I definitely would not try to solve it by flushing further at this point. If the lining material just disintegrated without galling the pump and the subsequent shifts in the tranny didn’t happen at low pressure thereby trashing everything, you could be lucky but thoroughly inspecting is now required in my opinion. I would have to rent another truck meantime to keep my business going. Do what’s necessary, otherwise you could waste a lot of money. Good luck.