Technical ID tri 5 rear end

Hi
Checking how do you id Tri 5 rear end?
Gm stamped number 3725899 on the diff.

 

57-64 non posi unit.

 

So this rear end won’t be easy swap into 53? Just drilling spring perches

 

Well if you use the axle housing for the 5-7 drill the pads and use you pumpkin it’s all good.

 

Well the guy selling the diff claims it’s a tri5 rear end. But gm number comes back as 57-64

 

You said tri 5. I thought 1957 was a tri 5. He didn’t lie.

 

A picture might help a little.


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A picture would indeed help....the center is removable, and could be installed in a 55-56 housing, but we can't see the housing.

 

^^^As stated, Tri-Five rear end housings will have spring pads^^^. The 57 housing is the ONLY one with a drain plug, otherwise it's a 55-56, and those are the same. Re-drill the spring locator pin holes 1-1/2 inches forward, and 1/2 inch inward (you could probably not drill them 1/2 inch inward); When we drilled ours the 1/2 inch inward, it looked like the springs were tilted in ever so slightly when looking at the car from the rear, but it was't a problem.
I am Butch/56sedandelivery.

 

Here’s the photo. The rear pumpkin cover has raised grove going down the the side rotation of the ring

 

Based on the only numbers provided (which was only the 3rd member portion) that's best best I could answer at the time. Now that I see more info and a photo do as other have mentioned when placing a "Tri 5 Rear End" under your 53.

 

The ‘55 and maybe ‘56 too (?) rear end housing used smaller diameter axle bearings, those could be a bit more difficult to locate if you needed them.
Sorry, but I don’t have a definitive way to ID a ‘55-‘56 housing.

 

No drain plug.

 

Is there a drain plug in the housing (NOT the third member/the cast iron center section)? 55-56 third members have slightly thinner cast iron construction, and the axle bearings are smaller, as already noted. The "new" bearings out there are all made off-shore, and are poor quality (imagine that!); if you can find NOS bearings, that's the way to go.
I am Butch/56sedandelivery.