4x4Wire TrailTalk

Ford 9in 28 spline

Posted By: Trailmonkey

Ford 9in 28 spline - 01/28/22 03:07 PM

From my understanding, the Ford 9" 28 spline is the same as the Monty 28 spline rear.
So technically a Ford mini spool or possibly lunch box locker would work ?

My main concern that I have yet to find an answer to, is the cross shaft dia.
For has a 3/4" shaft. Is that the same as the Monty ?

And if this is all true why can't I find any info on anyone doing this.
Posted By: OldColt

Re: Ford 9in 28 spline - 01/28/22 08:22 PM

One would truly have to look into this but if I recall the overall dimensions of the unit and ring gear mounting are not easily compatible. Look around for a MM rear LSD, I have not looked in a few years but there were some on Car part. Once you do the plate restacking they grip quite well.
Posted By: Trailmonkey

Re: Ford 9in 28 spline - 01/29/22 03:26 AM

I was not talking about the whole diff unit, just replacing the insides with a mini spool or possibly a Trak Lok lunch box type locker.
VS just welding it shut, I'd rather not do on the smaller 9 inch 28 spline unit.
Now if I had the bigger 9.5 inch 31 spline I'd just weld the sucker.

But I've seen Dana 44s welded with 31s and had no issues with limited street use.
Montero 9 inch 28 spline from what I'm told-read and heard is as strong or stronger than a 44.
Posted By: OldColt

Re: Ford 9in 28 spline - 01/29/22 06:58 AM

I was talking about the differential unit which one bolts the ring gear to. Not the whole drop out.
If you had a 9.5" why not just add a compressor for the air locker?
Posted By: Trailmonkey

Re: Ford 9in 28 spline - 01/29/22 03:29 PM

Same reason I'm not out beating the bushes for a 9.5 just don't have the funds for it.

And no I'm not even talking about the carrier the ring gear bolts to, but just replacing the spider gears inside the open diff.

1, mini spool.
2, lunch box locker.
3, locker inside the open diff.

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