Junkyard 9 inch with limited slip, ?

[Dpgoat]

Guy down the road has a 78 truck 9 inch with a limited slip and 325 gears. I have 325 gears but no LS. Could I just install this center section onto my stock unit using current axels? He wants 150 for the whole rear end.

 

[73pony]

Couple of things to consider. Spline count of your axels vs the spline count if the new third member. (28 or 31 spline) must match. Also the yoke. Length will dictate if you need to shorten drive shaft or get longer or will work ok. All depends if you have a long or short yoke and what the new one has. Also consider the U Joint size. Some of the Mustangs (my 73 included) have a pretty odd ball Ford BC 1310 yoke. Takes a 1310 u-joint but with the larger 1330 caps on it. Hope this helps. The yoke length and u-joint are fairly easy to overcome. You can always replace the yoke on there with your yoke and new crush sleeve to eliminate those two. The big issue is the axel spline count.

 

[Jeff73Mach1]

If the yoke is the same length, and fits the same u joint pattern then probably so. The axle count could be 28 or 31. Generally the 31 spline axles have 2 holes in the center of the face and the 28's have a sort of rectangular recess with rounded ends. If the spline count is correct, then it should swap in.

You should know how to measure backlash, check gear pattern, inspect the bearings and have a feel for pinion bearing preload based upon how it feels when you turn it, to be sure it isn't going to whine or roar excessively. The price is great. If you put it in and it whines too much, it still is well worth the price as a core for parts to build a fresh center section.

 

[kcmash]

Yep the others that replied are correct. Is the 3rd member from m the front axle or the rear? I got a 9 Inch LS from the front of a 4x4 that was a 3.25 also. The Yoke on the pinion is shorter and smaller than the original rear for my 71. See my recent post on the frustration with the rearend.

I had mine rebuilt by Pete and Jakes on the south side of Kansas City. I called them to ask what to do about the wrong pinion yoke. They told me the smaller size would be no problem and I should just buy a transition ujoint and I will be fine.

 

[will e]

Was there such a thing as a 9 inch front axle? I though ford used D44/D60's in 1978 but I am no expert. (I do have a D60 'sno fighter' in my Jeep from a 78/79 ford.)

 

[Dpgoat]

Thanks everyone. I would think that the truck axles should be 31 spline. If they are, I'd have to have the truck axles cut down.?? I'm I thinking about this right? That sounds expensive.

 

[Jeff73Mach1]

nah, cutting down axles is no big deal, just use a good metal blade on a chop saw, bevel the cut end with a grinder just enought o relieve the sharp edge and if necessary debur with a file (if you use a good blade, this probably won't be necessary) 31 spline axles are not reduced in diameter at the spline like the 28 spline are, so shortening them up is no big deal as long as there is enough spline left afterwards. Actual spline engagement in the rear end is fairly small.

 

[Carolina_Mountain_Mustangs]

I cannot speak for what is in the truck. I can say that a 1969 Ford E-100 long box van has the exact same rear center section as a Q code does. Same yoke and all. I have one and it is also an N case. Axles are 28 spline. I think the bearings on the axles are larger on the van / truck but cannot say 100%. Of course the rear is way off set on the van with one short axle and one long so they do work.