when im on the throttle its fine,until o.d. around 2000 rpm if i step down hard it will buck on me .. WHAT IS HAPPENING ??? can any one help me here ? thanks ..

 

It's the torque converter slipping most likely

 

With horse power, it could well be...if tranny is stock!
When slipping...rpm goes up but speed doesn't. Bucking may be first sign of problem. Cut back on power till you can get tranny built for power and it should last quite a while.

RJ

 

larger tires and a fueling box,,,,,,,,convertor aint gonna like that............try turning level down on your juice and see if it helps.............bama

 

another thing you can do is don't let it lock up until your at a safe speed where you will not get the shudder

 

Could also be voltage jumping up and down, check alternator, that was my problem.

 

Likely the converter is going if stock -- mine did. Note that you can change the converter and valve body now without ruining everything - adjust the bands with the change -

Check the fluid to see if it is burned - if it continues slipping it will be. I got a DTT Converter and Suncoast valve body from Farmboy's Diesel Performance and am totally happy with it. Also went deep pan. The rest of my trans is original at 150000 mi and I hammer it all the time on 30 miles of steep mountain roads, 12000 lbs empty with welder and tools.