I own a 2003 Lightning with the 4r100 trans. My trans started acting weird about 2 weeks ago. It started slipping from first to second. So i pulled the pan to change the filter and have it flushed. The pan was clean, no type of clutches or any other parts. It was very clean for the miles it has on it. So i had the trans flushed and that didn't help. If you take off easy or anything under half throttle the trans shifts fine like its new. After you pass half throttle it slips into second, but after it shifts second doesn't slip at all. But when it does finally shift to second its a hard shift, hard enough to bark the tires. And all the other shifts are firmer than they use to be. Could my valve body have something wrong with it? Could my throttle position sensor be bad? I don't think i have a ftvb because there was no writing on the side of it, as far as a line mod i don't know. Any help would be appreciated. Thanks Lil John

 

Yes it could be a sticking valve body, it could be the 1-2 shift soleniod or servo. What year? There was a TSB for the 1-2 shift servo on some '97-'00 I think. I have done a few.


Shane