2007 GMC Sierra 1500 four-wheel-drive. I was driving to work the other morning and I blew the upper transmission line off the transmission lost all fluid and of course my vehicle slipped and slipped until I finally couldn’t move anymore, Spent several hours repairing the line, getting a new one putting it on, added fluid, drove home fine, it drove 25 miles to work the next morning fine, Halfway home from work it started slipping again. I pulled off the road, started driving it again, it went in first fine, shift it into second fine, and does not shift out of second it tries to but then it slips and revs high and I can drive it in second gear but I’m afraid I’m gonna hurt it. Then I noticed I didn’t use dexron 4 for transmission fluid, I drained it immediately, and changed filter but it still slips rather than going into 3 gear or higher, Any thoughts before I pull the tranny
If I understand your question, you lost all the fluid in your automatic transmission but continued to drive it until it "slipped and slipped".
Then you repaired the leak but put the wrong fluid in and drove 25 miles or more.
I think it's very likely that you have caused internal damage to the "clutches" and other components inside the transmission. I think it was the initial empty running and not the wrong fluid that did the damage although the wrong fluid may have contributed after a while. Hard to say.
At this point, however, you're either in need of a transmission rebuild or a replacement.
Sorry to be the bearer of bad news but the fluid in a transmissions serves multiples purposes but one of those is proper lubrication and cooling. By running it "dry" you deprived it of both of those and "smoked" it internally. I have no doubt that on teardown there will be severely damaged components evident.