A serious question for you offroad guys, 'how much do you reckon the front differentials moves up and down approximately?? - typically, is it say 6" upwards and 6" downwards on a very demanding offroad course' it would be useful to know when thinking this idea of an arrestor through bearing in mind it would be located more towards the rear nearer the transmission (cardan) end therefore I guess somewhere like 6" to 7" diameter by 12" to 15" long with lateral lugs welded each side and held to the chassis with seriously heavy duty rubber mountings.

 

The front is a radius arm setup with a panhard and short shocks, it doesn't flex too much.

 

Thanks ZGPhoto, when it stops raining here and the hail stones stop falling I'll take some photos of the underneath of the truck and work up some ideas for a shaft restraint system. My other idea is a steel or aluminium tubular ring around the shaft and suspended on 3/8" diameter steel cables each side from rubber mounts on the chassis. If these ideas fly I'll certainly market it as there seems some limited demand.

 

Personally I'd care more for a guard for the driveshaft side of the tranny than a restraint.

 

Here are some pre-existiing ones that you might start from:

 

Thanks SuperSport, they are very much along the lines I was thinking of or a cross between both of them. Maybe using thick 5/16" aluminium though and rubber mountings to cut out resonance (like engine mounts) for mounting the lugs to the chassis or somewhere similar. I'll work on it and see what I come up with. My main aims are it has to be simple, effective and easy to install otherwise no-one will use or want them.

 

ZGPhoto, you are right in some ways but if you stop the driveshaft from flailing around it will stop the damage to everything. ...............hopefully. If you are on the tarmac and the cardan blows the shaft will bounce off the road and flail around albeit the truck will have no drive and come to a halt sooner or later, of course, unless you have CDL and it's engaged. But if the cardan literally shatters there isn't much anyone can do even with a restraint unless the cardan is in a restraint tube to stop the pieces 'grenading' everywhere. From what I have seen it is usually one or other of the UJ's that lets go first as the weakest point is where they are held in the cardan. I need to look into the setup and the stresses on the UJ/cardan junction and see what hoop stresses are exerted.