'53 Customline - Diff Gear Swap

[fredeuce]

I have a Ford style differential that was equipped with a 39/10 gear set. (3.9:1)

I am attempting to fit a later gear set that is 29/9 (3.22:1 ) to this early housing. I have discovered it does not fit and requires some relieving to get it to fit.

Clearly, there are different castings for these differentials.

Has anyone encountered this before ?

Has anyone relieved the housing for this purpose?

Is there a way of identifying these castings externally?

 

[pistonbroke]

Yes the casting is different for the later freeway fliers but, the whole third member will bolt into the 53 axle housing. Tim

 

[petehoovie]

I have a Ford style differential that was equipped with a 39/10 gear set. (3.9:1)

I am attempting to fit a later gear set that is 29/9 (3.22:1 ) to this early housing. I have discovered it does not fit and requires some relieving to get it to fit.

Clearly, there are different castings for these differentials.

Has anyone encountered this before ?

Has anyone relieved the housing for this purpose?

Is there a way of identifying these castings externally?

 

[Newc]

52/53 Wagons use a different diff also Newc

 

[fredeuce]

After some closer examination of casting shown in the original post I had a look at another complete unit to ascertain if there was any difference. This unit has a 41/11 (3.73) gear set. Looking inside where my pinion is fouling I can see the casting is different and provides a relief in the area where the 9 tooth pinion fouls. Externally the casting is different around the filler plug area. See pictures. I am going to explore this housing and see if it takes the 9 tooth pinion.

 

[tubman]

Given the scarcity of these rear ends, could you please define the years covered by "early" and "late"?

 

[petehoovie]

After some closer examination of casting shown in the original post I had a look at another complete unit to ascertain if there was any difference. This unit has a 41/11 (3.73) gear set. Looking inside where my pinion is fouling I can see the casting is different and provides a relief in the area where the 9 tooth pinion fouls. Externally the casting is different around the filler plug area. See pictures. I am going to explore this housing and see if it takes the 9 tooth pinion.

 

[pistonbroke]

I think they were used from 49 thru 56

 

[tubman]

I think they were used from 49 thru 56

I knew that, but what differentiates between "early" and "late"?

 

[fredeuce]

I knew that, but what differentiates between "early" and "late"?

Generally speaking I think you can define early v late as Flathead powered v OHV powered however the use of an auto trans also determines the ratio used so the line between the two categories is a bit blurry.

 

[tubman]

Generally speaking I think you can define early v late as Flathead powered v OHV powered however the use of an auto trans also determines the ratio used so the line between the two categories is a bit blurry.

Now I'm getting confused. Is this an "early/late" (e.g. '49-'53 vs. '54-'56) or a "carrier break" difference? ("Carrier break" is were you need a different carrier for high ratios vs. low ratios.) Anybody know for sure?

Just tryin' to add to my store of "shoebox knowledge".

 

[Gene1949]

Kinda off topic but related. I would mag [particle] the axles. I broke 2 of them, one on each side.
And no, my 16 year old self wasn't present.

 

[fredeuce]

An update on my efforts to swap out the 3.22:1 gear set. I have now been provided with another diff centre which had as original fitment a 3.22:1 gear set. The major difference with the housing is that there is an extra rib just above the filler plug.

The interior has greater space for that large pinion gear. In these pictures following you can see a shrouded area over the relief for the large pinion gear.