I just finished rehabing and installing an 8ft. Fisher MM1 plow for the first time and low and behold on the maiden voyage I noticed I don`t have any more 40-43 mph driveline shudder. There is a problem though, I need to ballast my bed to compensate for the plow weight to the tune of around 500 lbs so I may be getting back to square one.
I suppose this phenomenon points to pinion angle but could it just be weak u-joints or carrier? The truck`s suspension is factory spec. I guess I`ll start with u-joints and go through the rest piece by piece till I find the culprit.

 

Yep, there's a plow package. When I plowed in Connecticut we did one of two things.
1.) Put a sander/hopper in the bed.
2.) Put sand in the bed.

Is the over front weight that bad? We had several 250's with just Boss V-Plows and they worked fine.

 

Yes, after buying the setup for short money I discovered the top of the plow was pretty punky under the paint (buyer beware) I took the plasma cutter to it and zipped off 4 or 5 inches right across the length of the blade. I had some good 10 or 12 gauge plate so I used that to add a new top section with an additional 4 inch curl over the top. Between the pushplates and the beefed up plow my a## end is up there.
On a side note I finally got my Mag Hytek diff cover done. Man does that thing look awsome! Six quarts of valvoline syn 75w 140 to boot.! Pricey stuff! I immediatly noticed a difference taking off on a sandy shoulder and from wet pavement the better locking action of my limited grip. I used the recommended amt of additive.