Not An H3 Prob, Please Help!

[marin8703]

the truck is a 2004. The engine is a Vortec 4.3L V6. Im not sure about the transmission, this is what it sais

"1500 and 2500HD Extended Wheelbase: four-speed electronic automatic with overdrive (4L60-E) (for less than 8,600-lb. GVWR1)"
and it also sais this RPO: M30.
heres a link if you wana take a look http://www.chevrolet.com/express/specifications/ and then sellect the transmission tab.

Thanks for any help. The dealer said he doesnt know what it could be, but he is certain its normal. I dont know how he can say its normal if he doesnt know what it is.

We're gona purchase an extended warranty from Gm in the next couple of days, cauze the bumper to bumper will expire in january, and we just want to play it safe for at least 20k -30k more miles.

Thanks for any help you can offer!