i baught this truck 4 months ago and unfortunately dont know much about it. it has 206k miles on it and until today ran great. before my only complaint was that the tranny hesitated to shift at higher rpm's when i got on it. it would wait a good couple seconds, and didnt gain any speed until it shifted into 2nd or 3rd. now it takes almost an act of god to shift into second. i have to do 3k rpm's and then feather the pedal just right to get it into second. the shift between 3rd and 4th are good as new. it will not downshift into 2nd either. going up a hill today towing.... i couldnt make it in 3rd, 2nd was not locking up, so i had to slow until i could make it in 1st and helpd up traffic. I cant see any computer chips next to the tranny or do i know of any work ever being done to it in the past. any clue what in the heck is wrong?
thanks
andy

 

i had the same problem with a 6.0L engine the other day, it was fine till it warmed up, it would down shift ok but like u said when u get on it hard it just stays at the same rpm for like 10 seconds

 

it has always been sticky hot or cold. the new problem seems to be the same way.... hot or cold its still messed up

 

Sounds like your due a tranny tear down. Now im not sayin thats the trick but it could be a number of things from the sounds of it i would say it could possibly be a transmission filter, or if you pull the pan and there is lots of fine to coarse metal shavings in there obviously and unfortunately its tranny work time. Dont feel alone though i only had 165,000 on mine when i had my main man charles hook me up with a rebuild and man i love it now!

 

I'm in no way any kind of transmission expert but, could it be the speed sensor back on top of the rear diff? I suppose if that was bad it would affect all gears.

 

i dont think the sensor is the problem. i relpaced one of those before and it didnt have any direct on the tranny before or after i did it

 

my buddies truck acted like you decribed. turned out to be a broke 1-2 spring in the valve bodie. Sonix valve and spring kit fixed it right up.

Diesel Rod

 

do you know the web link to where i can get that kit? im not a tranny guy. is it something that can be done from the pan without removing the tranny?