Transmission scare!
 

Anyone had a 1st Gen 4l60 e go into limp mode when in heavy traffic ? Then try to drive it the next day and it was fine? Kinda freaked me out coz I was stuck in second gear for 20+ miles.i know I need to change the fluid and filter and possibly the range pressure switch! , Anyone got any ideas?

Any codes in the OBD? Get someone at a parts store to check for any diagnostic codes that might be stored.

I would ge to a reputable trans shop that has the diagnostic equipment and expertise to read and analyze the data. Then let them change the fluid and look at the condition of the fluid and sediment in the pan. Then they should be able to tell you a lot about what's really going on with the trans. If you change the fluid and filter or go to a quick service shop and have it done, you may save a few dollars, but you are destroying valuable evidence.

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Figured it out
 

Well it turns out that the previous owner did not change the fluid for a really long time! If you don't change the fluid every 30.000 miles sludge builds up in the manifold pressure switch!!!!. It control s all aspects of flow to the solenoids including torque converter lock. Mine was completely clogged up and not worth the risk trying to clean it and reuse. Since it's right under the filter and 5 bolts and costs $ 60 at the parts store or $20 on rock auto I just replaced it. Now it works like new! So if you are having shifting problems this may very well be the culprit! I hope this helps anyone else having issues.🤘

Forgot to mention
 

It was also getting torque converter shudder in OD and slipping in 3 Rd sometimes or not engaging 3RD at all. And first to second gear harsh shift! First second is still not perfect but doesn't chirp the tires going into second anymore.