9" strength

[bigjake34452]

about how much torque do you guys think the stock 28 spline in my 69 could hold up to?

[basketcase0302]

bigjake,


They do take a lot of abuse!
My narrowed 9 inch would break U-joints before the 38" mudders would damage the axle. Saw one 9" axle shaft break before, (He had 18.4/16.1 goodyear tractor tires on the axle for a swampbuggy). I've still got my narrowed 9" and D44 that I will run 21.5/16.1 tractors on in the future.

Basketcase

[averagef250]

Depends how you drive. Torque spikes/shock loads are what break parts. A clutch dump in first gear with a big block is putting rediculous lb/ft to the axleshafts. Say 500 lb/ft at the crank X 3 for first gear X 4 something for rear ratio= 6000+ lb/ft. That's without figuring for shock loads.

[ima71 trucks are older]

torque input doesn't really matter. like any semi-floating axle its the weight on it when torque is applied that matters. At around 2700lbs vertical load the housing flexes alot and with only one bearing stablizing each shaft and the axle shaft actually carrying the vehicle weight, it starts tearing itself apart.