NEW Washer, drain leaks

We just purchased a new large capacity washing machine (old one was not large capacity) and now the drain pipe overflows if you use the medium or high water setting. The drain pipe is ABS 1 1/2" and runs approximately 20' before emptying into the 4" sewer line. Is this machine pumping to much water for the line to handle? Should I replace the 1 1/2" with 2"? I have run a drain snake all the way down the line and it appears to be clear. Any ideas?
Thanks

Washer drain

A washing machine drain should be 2". You got away with it before because you had a smaller washer that didn't put as much water out as the new one. Besides going to 2", you need to be sure you have at least 1/4" per foot slope, and the drain must be trapped.

Agree with Gary.
I would also suggest that when snaking the line, a power machine is used with the largest possible snake head that will fit into the 1-1/2" line, even if it means cutting the ABS drainage piping. You can also try raising the stand pipe, (above the trap) several inches higher.
If all else fails, replace the complete run with 2" pipng and use the least amount of fittings as possible.

The drain should also be vented within 5' of the p-trap. The p-trap should be 6-18" off the floor, the standpipe 18-30" tall, use 2" for the drain line, 1-1/2" for the vent and install a cleanout (washers can discharge a lot of lint with the drainage water.
Deb
The Pipewench