special order 1984 HD f250 6.9 idi diesel t18 4speed manual regular cab long bed 2wd dana 70 3.73 stock tires and ride hieght.

so I've had this truck for about 6 months and its always kind of shuddered when i start out in 1st or 2nd gear. just for reference, i should clarify that 2nd is geared at 3.09 so its essential my first gear. 1st or low gear is set at 6.32 making it basically useless if not towing. the shuddering is only when starting out and is subdued somewhat if i give some throttle. i dont think its related to a stall as the truck is geared plenty low and has ample low rpm torque. im 17 and relatively new to these trucks so id loved to hear from of you seasoned truck owners. my thoughts are warped flywheel, worn pressure plate, or maybe this is somewhat normal for such a rugged transmission.

 

My guess is the clutch but you should check it out, particularly things like U-joints.

 

Check your u joints first. They just eventually wear out and need to be changed. Put the truck in neutral slide underneath and turn the drive shafts back and forth looking for looseness in the joints on each side if the drives haft. (There will be play overall because the gears have space between teeth just look for play in the joint) Try for side to side and up and down play.

After that check for loose bellhousing bolts. (Mine came loose on one side, causing a weird clunk or something a while ago.) If you still don't find the problem it may be deeper in like a clutch problem, hopefully not but the tranny isn't a hard job to remove just heavy.

Here's a u joint I happened to find bad on my truck. You can see the play without touching it. The driveshaft was balanced aperantly very well not long ago and I still didn't feel a clunk or anything.