94 F250 Diesel Jumps When Taking Off

[bilbo]

I just picked up a 94 F250 with the NA IDI diesel and 5 speed manual. When I take off from a stop the truck shudders and hops. Once underway it’s smooth, and gear changes are uneventful. At first I thought it was me not doing things right. I’ve had many manual gas engine vehicles but It’s my first diesel I’ve owned and the first manual diesel I have driven and it’s a bit different so I’m not sure. Does anyone have any experience with these? Do I just suck at driving a manual or might there be something really wrong?

Aside from that it drives great and I now understand why everyone likes these for pulling. I think it only needs two gears, 1st to get rolling and put it in 5th and drive away.

 

[RonD]

Its most likely a clutch issue, well 99% sure

Not an uncommon symptom, and more noticeable on a diesel because of the higher torque at lower RPMs

Not noticed when moving as much because you are RPM matching and vehicle is moving so has inertia holding it at speed

When starting off the clutch is at 0 RPMs and engine is at 700 RPMs, so when you lift pedal the clutch has to match engine RPMs AND get rear wheels to start spinning to move the weight of the vehicle

 

[rusty ol ranger]

Failed input shaft bearings can also cause the symptoms described.

Actually wait...is the whole truck shuddeding and hopping or just the shifter?

If whole truck then yes, clutch/flywheel.

 

[bilbo]

It’s the whole truck. Like axle wrap, but even with gentle application of power. I’ve done a bit of internet research and seems like it could be contamination from valve cover or main seal leak or the dual mass flywheel going to pot. Planning to just drive it for now while I investigate why my Ranger suddenly started pinging. Once that’s worked out I’ll have to dig into this one further.