Here is all the Husqvarna tractors with Diff/Lock & Prices
YT42LS TT-K46CR $2,099.95
YT46LS TT-K46CR $2,299.95
YT42XLS TT-K46CR $2,649.95
YT48XLS TT-K46CR/LD $2,899.00---I recommend for you...true LSD
GT54LS TT-K66ELD $3,199.95
GT48XLSi TT-K66ELD $3,399.95
GT52XLSi TT-K66ELD $3,499.95
Here are all the Husqvarna Tractors with a Heavy Duty Transmission aka GARDEN, plow, blades, ground engagement and pulling your yacht.
GTH24K54 HG-G730 $2,899.95
GT54LS TT-K66ELD Price see above
GT52XLS HG-G730 $3,299.95
GT48XLSi TT-K66ELD Price see above
GT52XLSi TT-K66ELD Price see above
The CR/LD at the end of the tranny name means it is a LSD limited slid differential go to <tufftorq.com> and check them out. ELD is electronic diff lock...like the switch you described. On the new ones it has a small pedal to engage the diff lock, no switch.
sorry, I must get some grub. Later and happy researching!