Posted by Clint Dixon on Tuesday, August 09, 2005 at 5:51PM :
In Reply to: Help needed: Driveline noise posted by Mike (Montreal, Quebec) on Tuesday, August 09, 2005 at 3:36PM :
I have never had a truck with the NP420, so I may not be the best one to offer an opinion. But, I definately think that your rattling is abnormal.
What I would do first is to remove the PTO shift lever from the truck and test drive. A warn pivot pin in the PTO shift lever can cause the lever to viberate and cause all kinds of noises. Next, remove the PTO box from the transmission and install a cover plate in its place, even if you have to make a quick cheap one out of sheetmetal. Drive the truck and see if it still makes the noise. If removing the PTO from the mix does not help, it will not have been a total waste of time because now, with it off, the transmission will be easier to remove from the truck. If syncronizers are grinding to pieces inside of the transmission, the PTO needs to be flushed out and inspected anyway.
Also, before removing the transmission, try removing one driveshaft at a time and driving it on the remaining shaft. There is a chance that you may isolate the problem to the rear differential.
Hope this helps.
Junior