Knowing the year and model of the vehicle may not be good enough for positive identification of the installed unit. Some manufacturers will perform up grades or even change the models during the manufacturing year. The only positive way to identify the exact one installed in your vehicle is to get the identification numbers off the transmission itself.
Transmission diagnosis is not always automatic
Upon further inspection his transmission problem was actually a broken transmission mount. Replacing the rubber mount solved the problem and there was actually nothing wrong with the transmission itself.
As other examples problems can be caused by poor engine performance, problems in the hydraulic system, or even abuse resulting in overheating of the fluid. Mechanical malfunctions and electrical failures or even improper adjustments can also cause transmission problems.
I also like to take one of my auto scanners and make sure that there are no set trouble codes for the transmission. Diagnostic trouble codes if they are set can help reduce transmission diagnostic time. Often these set codes will direct you to a specific component that needs to be tested or inspected.
Learning as much as you can about not only your specific model transmission but an overview of how they work can also help you diagnose minor problems at home. In the example I mentioned above replacing a transmission mount on some models is not hard but yet on the other models it can be very difficult. If you locate a specific problem check your service manual to see what's involved with the repair or replacement.
This next link will take you back to the blog for online auto repair from this page about transmission diagnosis. If you would like to learn more about transmissions I have built a repair model on my you fix cars website that talks about specific automatic transmission problems.