Transmission problems

[nharroll]

So today I replace a trans cooler line, bottom line on the passenger side of the radiator. I added full synthetic atf approximately 1.5gallons. The truck drove about twenty minutes perfectly fine and then suddenly started to sputter real bad, and barely move. Then it started throwing range shift inhibited in every gear but reverse works fine... I'm really confused and need help. Any ideas?

 

[56taskforce]

Fluid level good???? Before you say yes check it again...

 

[nharroll]

Yes fluid level is good.

 

[mike diesel]

Exactly what fluid did you use?

 

[mike diesel]

Also, scan for codes with a legitimate scanner like a tech 2 or efi live.

 

[Ridin'GMC]

Did you make sure there was no contaminants or something in the lower hose?

 

[nharroll]

Nothing in the hoses that would cause problems. I'm under the impression I used the wrong fluid. I used a full synthetic valvoline DEX/MERC LV. I'm gonna drain it and put the DEXlll in.

 

[Chad006]

Not sure what clutches come in the ats tranny but I know dex 6 and my altos didn't agree. Dex 3 smartened her right up.

 

[nharroll]

So here's the latest update on the transmission. I drained all of the fluid put the DEXlll in and still only engages into reverse. Throws a range shift inhibited in every other gear except reverse and park. When in drive it feels like it's no engaging but moves slightly then says range shift inhibited. You guys think I should flush the trans and go from there?