98 caravan transmission died?

ive figured out limp mode and why service engine light is on for my 3.3 caravan se .... went to repair shop..they sent it out to tranny specialty place,,and said they pulled pan off and solenoid needs replacing,total cost 2100 cdn...now reviewing all the history of dodge trannys and how fickle they are.. mileage is 138,000 km.. owned for six months,,bought used,,, and one day after 2-3 hrs city driving engine light goes on and limp mode takes effect....is this because of overheating or its the time of tranny to die??
should i just get the fluid changed and new solenoid only put in?
any suggestions would be good..