We have a clog somewhere between disposal and sink. We tried a 3/8 snake and it did not fix the problem. What should we try next?

We've been working on this clog for over an hour with a 3/8 snake 25 feet long. It comes out pretty clean but the sink and disposal are "sharing" water back and forth. What should we try next?

The clog can be in the "T", right there, where sink and disposal drains connect under the sink. Did you check those drains first ?

A little more information please.
Where are you snaking from? Did you remove the bend from the trap and send it up in the wall?
If so and it didn't get the clog then it's farther down the line and must be snaked from the kitchen roof vent. Put out enough snake to reach the base and 18 feet more. You may need a longer snake to do this. Good luck, Tom