9 inch LSD into an open 9 inch

[jmorgan_68]

I have a 68 swb with an 9 inch rear end and have access to a 9" LSD out of an 85 bronco, is it possible to put the LSD internals into the 68 rear end?

[fordman]

the axle splines will have to be the same or get the right splined and lenght axles to fit your nine inch rear end tubes.

[jmorgan_68]

I pulled the axle on the LSD rear end and its a 31 spline. Im not positive but im pretty sure the axles on the truck will be 28 spline. Any idea what the length on these will be without me actually pulling it?

[forrestbump]

One thing that caught my eye is you stated:

I have a 68 swb with an 9 inch rear end and have access to a 9" LSD out of an 85 bronco, is it possible to put the LSD internals into the 68 rear end?

Now if I'm NOT mistaken, Ford discontinued using the 9" rear axle housing in either '80 or '81 for F-150's and Full Size Bronco's. If that's correct, your Full Size Bronco is going to have an 8.8 rear axle housing in it. Now if it's a Bronco II, it'll have either a 7.5 or 8.8 and be MUCH narrower than the Full Size Bronco.

Just thought I'd bring that up as the two axle housings and their components are different and will NOT interchange.

[jmorgan_68]

I ran the numbers on the axle tag (S319D- 3L50-9-5A09) which showed to be a LSD with 3.50 gears and a 9" ring gear. If this is the case will the two 9"s not interchange? And this is a full size bronco

[forrestbump]

The two axle housings have a visual difference. Look at the back side of the housing in your '85 Bronco... does it have an inspection cover held on by bolts - OR - is it smooth in appearance?

If it has the removable cover held on by bolts, it's an 8.8. If it's smooth and looks just like the rear axle housing in your Bump, than it's a 9".

Another BIG difference is the 3rd member is removed from the back in an 8.8 whereas the 3rd member in a 9" is removed from the front.

Now if both axle housings are 9" most parts MAY be interchangeable. '72 back 9" housings are narrower than '73 up. The spring pads are also in a different location (later Trucks have wider rear frames than Bump's). Axle bearings are also available in different sizes too (just to make your head swim).

At least the 9" carrier will accept different gear ratios up or down without having to change it so you'll be OK there.

Now if this were me, I'd use the Trac Loc third member, change side gears to 28 spline, slam it in and hit the go peddel.

Hope this helps.

[fordman]

our 9 inch rearend axles are 29 7/8 long. or it 5/8

[Hawkrod]

86 was the last year for the 9 inch so an 85 Bronco should be 9 inch but the 85 will have 31 spline axles and they are not the right length to use in an earlier truck. In order to use the 31 spline center in the 68 you will need to have 68-72 31 spline truck axles which are out there but are not that common when you need them! They came in all trucks with a 9 3/8 center and some heavy duty 9 inch rears as well. The 68-72 28 spline axles are 29 15/16 long and the 31 spline axles are 29 13/16 long. Hawkrod