Actually, a scan tool is the best way as you can monitor the solenoid activity and manually turn them on and off to verify signals. It will be well worth the money, unless you own an actual scan tool, to let a trans shop at least check it out for you, then after the diag is done, you can decide whether to fix it yourself or let someone do it for you.
Roy
Friday, June 1st, 2012 AT 1:48 PM