4l60e going out?

[What?]

S10, 4 cyl, 4l60e. currently 290k.

Previous owner thought trans was bad and swapped it, same problem persist (hard 1-2 shift), his was done before 130k on unknown mile transmission

For probably last 50k, 1800 to 2000 rpm, it would go up and down in any gear

Last 10k, around 160*, whenever 1800 to 2300 rpm, it would have shudder/heavy misfire few time then downshift to keep rpm at 2500 rpm. It would start when transmission reaches 160* and higher.

I was told clutch band is likely going out

And the valve body for the 1800/2k rpm up and down.

If that's the case, any suggestion for improved/upgrade internals when I get the shop to rebuild it?

 

[arse_sidewards]

Trash the 4cyl and install any used medium-low milage V8 and TH400 combo you can get for less than the rebuild would cost. Slap a super low stall converter in it (you can get away with that in a light vehicle like you have) to make up for the lack of OD and lockup.

 

[Oddball]

Although I love the idea of a V8 swap ( I've already done it), I think you just want to keep kicking this dead horse. The 4 banger gets the job done with minimal fuel. Maybe the issue is engine management, and its just showing its face in driveability. Hence the misfire. Check the coolant temp sensor and really all the sensors. Also check the ignition system. A 4L60E should last forever behind a 4 banger.