Issue with Trans.
 

Hey guys, I’m having an issue with my 99 2500 downshifting to 3rd and holding it once at high ways speeds (55-65) mph. I can drive around 45 mph with no issue, but once the issue begins it will start shifting hard (1-2) (2-3) gears and will not hit OD whatsoever. I can cut truck off and sit for a minute and it’ll go back to normal shifting smooth. I have replaced internal wiring due to fluid in connector, but issue remains. I took it to a shop and they said it had loss communication to TCM and trans slip I had them reset the codes but the issue came back after a mile or two down the road. Any advice would be appreciated!

Have you tried having it scanned for fault codes? Can you tell me what codes show up?

Sorry for long absence but I just wanted to let whoever might come across the same issues as I was having but took it to a actual transmission shop and they suggested a new torque converter and it has seemed to fix my issue.

had a similar issue in my 2022 Silverado with the 2.7L turbo. seemed to be a software glitch that cleared itself after a few drive cycles, but if it happens to you I'd suggest trying the uconnect software update and seeing if that resolves the problem.

Had a similar issue with my 2022 SS, turned out the TCM was glitching so I just reprogrammed it and it's been smooth sailing ever since. Have you tried resetting the TCM or scanning for any codes?

I've seen that a few people have had issues with the 10-speed auto in the '22 Silverado, it sounds like you might be experiencing some jerkiness when shifting into gear, if that's the case, try checking for any software updates and make sure all the sensors around the transmission are clean and clear.

Just had a similar issue with my '22 SS, turns out was just a loose TCM connector, cleaned it up and problem solved, might be worth taking a look for you. Also, are you running the 10-speed or the 8-speed?