Can I exchange the center chunk on a 9" rear

[prayers1 153]

I have a 9" 28 spline trac-lok rear with drums. I'm wanting to go to a 31 spline set up. I know the axles are different, but will the center chunk that I have now fit on a 31 or big tube housing.

 

If anyone has a Big Tube - 31 housing or parts for sale, please let me know.

 

Thank you!

[BandBSTANGS 15]

To my knowledge the only difference is the splines on the end of the axle and the actual spline count on the inside of the traction lock...spool...etc.

Actual center section/chunk can be built either way.

[1969_Mach1 333]

You do not need a large tube housing for a 31 spline axle setup. The main differences are obviously the axles, the side gears inside the trac-lok unit and sometimes the trac-lok housing (not the third member). I say sometimes the trac-lok housing is because I was told by an older Ford technician the axle pass through hole in the sides of the trac-lok housing are sometimes different sizes depending on if they were for 28 or 31 spline steups.

 

The only other difference I am aware of is the axle seals. The OEM 31 spline axles have a collar on them where the seal rides requiring a different seal. The axle seal has a larger I.D. I think the collar is being reproduced and I have seen it in NPD's catalog. You can do like myself and most others do is reuse the 28 spline seals and not install the collar on the axle shafts.

 

I have a 31 spline NOS Ford trac-lok unit with 31 spline Moser Engineering axles in my Mach 1 and it has a small tube 9" housing. No issues with it. I say small tube housing because it uses the smaller O.D. axle bearing.

Edited December 14, 2014 by 1969_Mach1

[mystangalang351 12]

What ratio do you have? Im looking for a 3:50 with 28 spline

[1969vert 55]

Yes and no...your carrier could be a small bearing and the 31 spline might not slip in if it is a factory traction lock...or open carrier ...most after market carriers use the big bearing and can be 28 or 31 splinter.......housings ....will work also but.....small bearing will not except the big bearing carrier.....if you have the big bearing third member...3.06 bearing diameter and carrier you are good to go with 31 spline...hope this helps...might just pull it out and do some checking....and see if you need more stuff......by the way I run the small bearing housing in my car and it works fine...just stuffed it with 31 spline stuff...

Edited December 14, 2014 by 1969vert

[prayers1 153]

I have a rebuilt 9" 28 spline rear with 3:50 trac-lok and drum brakes.

 

I posted the same question on VMF and the thought is to keep what I have and get a stronger yoke. The yoke on the driveshaft is larger than the one on the pinion yoke.

I have to buy 2 different universals to make it work

 

This Winter I plan on changing to 3:89 or 4:11, I have the 351C 4V with an AOD and a 2600 stall. Yesterday I put on my old 295/50/15's and felt a big difference on take off then the 275/60/15's and besides when I had the AOD built I told the builder that I'll probably be running 4:11's.

[1969_Mach1 333]

You can replace the yoke. But its a little more than a direct bolt on replacement. You will need to check the existing pinion bearing preload and match it closely when reinstalling the new yoke. If you also replace the pinion bearings then you don't need to match the preload, but preload the new bearings to spec for new bearings. It's easier if your pinion uses a solid spacer instead of a crush sleeve. With a solid spacer, if you are not replacing anything else, you simply retorque the pinion nut to specs with red loc-tite compound on the threads.

 

Plus I'm not %100 certain but the 3.50:1 ratio might be what is called a non hunting gear ratio. Meaning the same pinion teeth and ring gear teeth mesh together on regular intervals. If so, I understand you are supposed to maintain the ring and pinion tooth mesh relationship. (I hope that is understandable)

[mystangalang351 12]

If you decide to sell I would be a buyer at 400 shipped

[prayers1 153]

Thank you for the offer, but I have 800 in the rear alone and to ship it would cost much more. You would be better off finding a used one to rebuild.

[mystangalang351 12]

thank you

[mystangalang351 12]

thank you