4L60 stops pulling after 40 miles

My son has a 1999 Sierra pickup 5.3 w/4L60E towing package came with truck.
The trans was rebuilt about a year ago with the "upgraded" sunshell and other various parts. The shop has a great reputation.
Today the truck was driven about 40 miles, then slowly disengauges from pulling the vehicle. (will not move, like it was put in nuetral) Shut the truck off for 5 minutes it will drive normally for about 1/2 mile then the same diengaugemnet of the trans. My son checked the fluid about a week ago and it was fine. He checked the fluid (engine running and now it is over full) The "service engine light came on (today) after this occured.

Any information on what is or may be causing this, or which way to go forward would be appreciated.

Thanks
Camaro1967Rs/Ss :rolleyes:

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The code is probably P1870 but you should have it scanned to be sure. Also, a transmission capable scanner should be used to diagnose the transmission. It can verify shift solenoids and line pressures.

Start with the code(s) and go from there.

//2000CAYukon

Thank you for the reply, we contacted the same shop they have the equipment for what you suggested.

Thank You!!

Camaro1967Rs/Ss :)

Well we found out the torque coverter was lunch (1 year old :2cents: ) caused issues with the band due to metal contamination , a few of the soleniods for pressure adjustment got shot also.

Bottom line we replaced the converter, bands and clutch plates, line pressure solenoids...$750.00 total for the fix. The shop said the converter went south for some reason...not sure why. Hope this may help some others that may have a relative issue, and thanks again for the help. :popcorn: :2cents: :grinyes:

Thank You!!

Camaro1967Rs/Ss :)

A torque converter is what killed the first TH 400 in my truck at only 92K. A fin broke in the TC and cause a cascade effect and eventually literally destroyed the entire transmission. In every crevice of the thing you were able to find metallic particles.