2001 Tahoe transmission issue

[dougefrsh]

2001 LS, 5.3, 4 x 4, 187,000 miles - no previous transmission issues as far as slipping or problems getting into gear. Driving home and lost all forward and reverse gears all at one time with no warning. The vehicle will go into 4-low/4-high. Is this definitely a transmission issue? Has anyone had a similar problem? It's not low on transmission oil, and there was no burning smell. Thanks for your help.

 

[OR VietVet]

Hopefully @NickTransmissions can help.

 

[NickTransmissions]

2001 LS, 5.3, 4 x 4, 187,000 miles - no previous transmission issues as far as slipping or problems getting into gear. Driving home and lost all forward and reverse gears all at one time with no warning. The vehicle will go into 4-low/4-high. Is this definitely a transmission issue? Has anyone had a similar problem? It's not low on transmission oil, and there was no burning smell. Thanks for your help.

Does it move when in 2H?