transmission problem question

[2007chevysilverado]

I have a 2007 silverado the Trans will just kinda float more less in second gear it will Rev up and catch and add soon add it catches it will do it again and when you mash on it to catch the passing gear it will just wrap the tach around to 5 grand and never catch in talked to a few people and they are saying it needs to be rebuilt. What do yall think about it? I have a 01 denali with a 4l65e will that Trans work in my truck?

[gmtech4]

3-4 clutch is done ., rebuild or replace it with a rebuilt unit ,

 

Of course always have it road tested by a garage first