hi all,new to the forum..it looks like a great place.
i'm having a problem when my fuel tank goes below 1/4 tank the trans starts shifting really hard(bang)...if i shut the truck off and restart it's fine unless i don't get gas then it starts the hard shift again.the light comes on once in a while.the dealer where i bought it from in aug 05(w/63k miles) scanned the trans(charged me $90)and said everything is fine.i replaced the fuel filter and gas cap thinking this may affect fuel pressure..didn't help.the truck now has 73k on it...the dealer said i should flush the trans(for $150)..i don't really think that's going to cure the problem.has anyone ever heard of something like this problem?would appreciate any help i can get..thank you

 

dude, can't say i've heard of that, but you didn't mention, how's the pressure while it's doing it.. and it could be that the fuel pump strainer is really dirty, or that the fuel pump is just over heating when it's not in liquid, cause it does use it for cooling

 

thanks viper,haven't had the fuel pressure checked yet.i've been doing some seaching on this and it looks like i may be in for a costly trans rebuild...that sucks,i've only had the truck 7 months...

 

I had this exact same problem, no error message would show on the computer until it got really bad. It was shifting really hard (banging) into 2nd, 3rd etc. I always had to shut off my truck for a few seconds when it was acting up. This would make the problem go away for awhile but it always came back. Found out it was my valve body in the tranny. I had a shop put in a new revised valve body and now she shifts like a Cadillac.

Your thread here reminded me of what my truck was doing exactly as yours.