Bad vibration

[Panther M75]

Posted earlier, but I'm not sure if the system crashed or if I thought I posted.  Anyhow, I have a slight problem with the truck, and I cannot figure out what exactly the source is. It isn't so noticeable in park or neutral, but when in drive with the brakes applied, the truck shivers ridiculously...even my windscreen mounted rearview mirror vibrates. It is noticeable in park or neutral, but only slightly. It's only in drive that you really feel it...even when you're in traffic and moving forward a bit, where it vibrates really badly. It jerks and shakes as if its a manual being operated by a new driver. The RPMs do not fluctuate and remain the same though. Could this be a dirty MAF or IAC, or possibly the fuel filter? 

Speaking of which - the timing belt, spark plugs, head gasket, water pump, air filter, thermostat, PCV valve, fan clutch and radiator hoses have all been replaced recently. It also gets an oil and filter change every 5,000 km (3,000 miles). Cheers!

[Sparks]

Yes, something strange seems to have happened yesterday
I read your previous post, and several others too, including some I responded to! All had disappeared when I came back late last night!
One of the respondents to your post asked about the rpm at which this occurs
I would also be wondering about the state of the engine/tranny mountings! If any of them has collapsed allowing the power unit to touch the body/chassis, the resulting vibes will be pretty spectacular! I had this on an old (petrol) Sierra once! The sump was sitting on the crossmember. At certain points, under accellaration, it would shake your fillings loose, but at all other times it was quiet as a mouse! Took ages to figure it out!

sparks

[Panther M75]

Cheers, Sparks! It only happens at idle speed (750-900 rpm), if you rev it up the vibration completely disappears. I'll get the motor and transmission mounts inspected once I return in just over 10 days, although I was wondering if the distributor or plug wires could be getting old?

[TinyTim]

Ah well - I can explain what happened. We had a srver problem and had to restore the whole thing from a back-up that was about 12 hours old so any posts mad in those 12 hours were lost. Sorry about that but these things tend to happen and it could have been far worse. 

I'm also thinking motor, gearbox, transfer box or even exhaust mounts.
Especially the one on the side of the transfer box as thios failed on my 2.5 and that was quite dramatic.

May also be worth checking the crank pulley is behaving tho I'm not sure they are as suaceptible to failure as o0n the diesels.

[Panther M75]

No problem at all, Tim! These things do happen. 

You also hit the nail in the head! I just spoke to my father - he told me the battery light came on and the engine started running much warmer than usual today. He took her into the dealership and the crank pulley had broken, causing all the serpentine belts to tear. They pulled out the front end (radiator, etc.) and replaced it. The engine running warmer than usual was a common problem for the past 2 months, and I couldn't figure out what it was...now not only does the coolant temperature remain at 82 degrees, but the vibration has completely disappeared! Thanks, guys! That was solved really quickly! 

[TinyTim]

Phew - Just as well as they can make a right mess if left too long.

Good to hear it's sorted mate