matt dillion

98 cummins , lift pump , 100 hp injectors, edge 5 setting mod, modifided intake manifold, cold air intake , straight pipe exaust,100,000 miles... i run it on setting two for the most part,{420 hp-780' lbs.}transmission shutters under light throttle, when locked up in or out of od,from what ive read , sounds like it is a throttle control issuie any one got a fix , or anything that might help me ,

VADSLRAM

?
Major font faux pas

anyway
What do you mean by shudder? Not locking up or jumping in and out?
if it truely is a shudder then time to look at your bands and figure on a tranny rebuild. Could be caused by clogged filter, low fluid, too much HP or faulty solenoid. But the end result for all is fried bands and possibly an entire clutch pack fried.
If it keeps hopping in and out of OD then it could be the dreaded electrical gremlin that out trucks get. I finally fixed mine with a cap/filter in the tranny lockup wire. I don't have the exact part # or source here but if you search my posts I know I put all the info on here when I did the job.

J BODY

Basically you've learned the lesson that when you upgrade power, you need to upgrade the WHOLE PACKAGE. You'll find a really nice bluish/purple ring on your torque converter when your trans is removed for the overhaul and upgrades.