"service engine soon" codes

Last night my "service engine soon" light came on my Dodge Caravan. It was shortly after putting Chevron Techron additive in the tank so I thought it was just running rich gasoline but it stayed on all day My van wouldn't go more than 40mph on the freeway so I pulled off, had a guy at an auto parts store read the codes, they are as follows:

PO715, PO732, PO731, PO700
(Transmission circuit A, gear ratio 2 incorrect, gear ratio 1 incorrect, transmission malfunction indicator lamp request, input shaft speed sensor checked)

First, in 2008 I had a new transmission put in by Aamco with a 1 year or 12,000 mile warranty, which ever comes first. It's been over a year but since then it has only had about 4,000 miles on the vehicle, Is it best to take it back to them even though the warranty is up or to the Dodge dealer who I trust?

Also does this sound like I would need a whole new transmission (again) and would the Chevron additive caused the problem?

Thanks
Cl8

I doubt some fuel cleaner caused a bunch of transmission codes to pop up.

Not going over 40 sounds like the van is locked in 2nd gear for limp mode.

Call Aamco and see what they will do for you. If they won't help, then off to the dealer. It could be an issue with wiring or the TCM.

Thanks for the input vgames33