98' 12v Cummins Acceleration Shudder

[RCReitz]

When driving my truck on back roads or on the highway without a load, occasionally if I lean into the throttle a little heavy, the truck will begin to accelerate, but once it reaches between the range of 45-55 MPH it begins to get a violent shake/shudder that will rattle the whole truck. The rattling goes away when I let out of the throttle, or sometimes goes away after I continue to accelerate further. I don't believe it a TC issue, but I won't count anything out. I don't believe its a fuel issue either because I have normal pressures at idle and driving. Since the issue began, I have replaced the OFV, changed the transmission fluid and filter, change the fuel filter, and replaced the lift pump (stock). I am looking for any suggestions of what to look at before taking the roach to a shop and spending money I don't need to.

On a side note, my steering has also been a little loose and I experience a violent shake / shudder under faster speeds when hitting a bump with the wheels turned at all. I can't say its a related issue or even that the shake I feel is the same, but if there is chance its related, I figured I'd throw it in.

 

[GAmes]

Are any of the throttle springs broken? There should be two on the p-pump and one on the throttle linkage.

 

[DVolk]

Could it be the Overdrive acting up

 

[SMalafy]

I have that problem with my 95. Does the shudder go away when you push the button in to shut off the over drive ? I was told by a mechanic the transmission was not able to make up its mind staying in 3rd gear or shifting to 4th overdrive. It usually goes away when you get above 55 does it not ? The shudder goes away on my truck and I was told it is nothing to worry about. As for your steering try a new steering damper if your present one is bad or leaking.