28 or 31 spline
 

does anyone with a 77 ranch 400 engine know what their spline count is.
I changed axle bearings about 4 yrs ago and didn't right down what I have.

I am getting ready to purchase a complete 3rd member to get rid of the open carrier and to replace the stock 3.00 gears with 3.50's
if someone can save me the hassel of pulling an axle that would be great. :D

I would bet yours is a 28 spline. 31 and 35 are for big HP.

ranchero it's too easy to pull an axle and count the splines to go in blindfolded. Shouldn't take but about 20 min.

John :-X06

I think its the 31.
after 1970 all the rears used the bigger dia 31 pline axles and the ends were turned down for the 28 spline application. I don't remember the end of my axles being tapered down.
I will probably pull an axle this weekend to be sure.

update
 

I was just reading a topic on 9" rear in 73-79 trucks and found a good tip. the bolt size on the axle bracket to brake assembly plate indicates what axle spline. the 28 being 3/8-24 (9/16" bolt head) and the 31 spline is 7/16"-28 (11/16" bolt head)

I think I would have trusted this info beforehand but I did pull the axle and it is 28

now its time to order my traction lock! the race track opens March 7th :D

i've read that a 28 spline has a "hollow" or "dished out" center hub and a 31 spline has 3 small holes in an otherwise solid, flat across center hub.