Bad vibrations m1008 except at idle.

[WARWAG]

Not sure if this is the same thing but My truck had the exact same vibration you are describing. It was driving me MAD! I thought it was my glove box. NOPE. Then maybe it was my dash. NOPE! Its was impossible to track down and was loud as **** inside the cab. I then thought it was my exhaust system, motor mount, tranny mount.....SOMETHING under the truck. Turned out to simply be my T-Case shifter knob! It was slightly loose and made the worst sounding vibration noise in the cab. Unbelievable. I discovered it when I was off roading with the wife and reached down to shift out of 4 low to 4 high. I grabbed ahold of the knob and the vibration stopped! Tightened it up (didnt even know it was slightly loose) and vibration gone. Hope this helps.

 

[allenhillview]

Three weeks ago started up my 1008 and headed to work .got to the bank and noticed a vibration in addition to strange noise. Got my banking done and headed out.I was in a little of a huryy so I was cruising pretty fast (55 mph) all of a sudden vibration increased then the alternator light went on. Before I had a chance to process all this data engine stopped. Immediately !! Coasted to a stop and realized that I just blew the engine. I got this truck almost straight from the military at 59,000 miles. It now had 73,000 miles on it but I have been anal about oil changes and maintanence.I have always used Amsoil HD 15w40 diesel and had made many medium range trips. Motor has always been solid and dependable so this was a mystery to me. I have never blown a motor in anything that I have owned for a signifcant time so I was determined to find out why this happened. A friend fortunately had a military 6.2 J motor for short money so I tore the motor out immediately. Couldn't turn crankshaft to get flywheel bolts off so I pulled oil pan and started pulling rods and mains. Every bearing was mint. no metal in pan but block was demolished and crankshaft was broken into three seperate pieces. One of the pieces almost hit me in the head when I got the rod bearings unbolted. Finally got crank off and sure as *&*^% thye harmonic balancer had sheered the key off the front of crank even though the bolt wasnt noticeably loose. Needless to say I bought brand new balancer and key for new motor ,but any 6.2 diesels I have in the future will have a thorough inspection of the balancer key and related parts so that might be something you might want to at least check. Love this site and hope this adds positive advice

Where was your source for the balancer (harmonic) mine is a little off at idle sure it smoothes out at more RPM's still there just can't see it?