Heres the scoop, i recently purchased an o1 e/c s/b. a week or two later it had to go in for injectors with 97000. in the mean time i picked up the edge juice w/ attitude. the truck went in for injectors and when i got it back i went through 16 gallons of fuel in 40 miles. Had it towed back to the dealership and come to findout gm sent me 6 out of the 8 bad remans. three weeks later i have my truck back put the juice in. running great 97 in quarter mile, etc. let my father in law take it for a ride while i was in the cab and it over revved when it downshifted into 4th. my moniter said it was still in 4th so we stopped to see if it would downshift through all the gears. it wasnt happening.got it back to the house shut it off so it would reset, took it for a ride and it seems to upshift and downshift fine but my ses light is still on and cant get it ran on the scanner til tomorrow. Any ideas?

Sounds like a tranny limp.

thanks for the info man, much appreciated

Moved to Allison forum....

Sounds like trans to me also.