Rear differential spline count

What year did the rear axle spline count change from 10 to 19?

I was going get a locker but don't want to end up with something that will not work. Mine is a 1964 and have been told it should have a 10 spline rear.

Thanks LG

 

You should open it up to check to be 100% sure. My 64 had 19 splines, but I opened it up and counted to be sure. With the age of these jeeps, anything could have been done to it in the last 46 years.

 

:iagree:

Anything could have been put in there in the past. I even came across a rear end once that had 19 on one side and 10 on the other.

 

The change from 10 to 19 spline came about when Spicer was developing the Thornton Powr Lok very late in the 1956 model year.

 

My 62 has 19 spline pull them and look.
Posted via Mobile Device

 

I know some Marine Corps M38a1's with 10 spline Dana 44 rears came from the factory as special order with Powr-locks. The side gears are hard as hades to come by, but I know they were built that way. I've seen/held them in my hands.

 

yeah my 67 has weird spine count also, I thought it was the 19 and when I opened it the inners were all 10 spline, wow who retrofitted backward? So I called Herm and got modern ones and through in a brand new locker

 

Sparky,
I'd be happy to disclose my sources if you are interesrted in knowing how I arrive at the given timeline.
I really need to go back and verify the information anyway from time to time since long term memory is seldom dependable.
It's been a while since I looked it up and I don't find the documentation on my computer storage.
Most of my info is filed away at home on paper and not on computer. No books with me at this time.

That fits with my understanding.
The first prototype's and very early production of the Thornton Powr Lok were 10 spline units.

 

I'll pull the cover. Is a Detroit Locker, lock right, or mini spool better? I know which ones would be easier to install? Of course my choice will be limited depending on spline count.

Anyone know of a manufacturer for a mini-spool for a 19 or 10 spline Dana 44? I have searched and email a few companies and no luck find in one.

 

I've got a lock-right locker in my 19 spline dana 44. I'm happy with it. Easy to install and probably the easiest to get, unless you want to look for a used Powr Lok.

 

Extracting information from documented sources is part art and part science.
Below is my extraction of the "Dana 44 Involute Spline Timeline".

Willys Parts List Model CJ-3B Universal and Farm `JEEP`
Willys Motors, Inc. copyright 1953
GROUP 21-01 Rear Axle
# 802845 Axle, rear assembly ( 5.38 to 1 ratio)

Note: the part number and the description.
To fully understand our jeeps we need historical perspective.
This book documents the CJ rear axle standard for 1953.

`JEEP` Parts List WILLYS Model CJ-5
Willys Motors, Inc. Issued July 1955
GROUP 21-01 Rear Axle
# 802845 Axle, rear assembly ( 5.38 to 1 ratio)

Note: that the W/O part number does not change.
This verifies that this same axle was still used for CJ applications in 1955.
From "hands on" experience we KNOW this is the 10 spline version of the Dana Spicer Model 44.

Willys Motors Inc.Parts List `JEEP` Model CJ-3B
(second edition) Issued November 1956
GROUP 21-01 Rear Axle
# 912216 Axle, rear assembly (5.38 to 1 ratio) (W/involute splines)
# 911822 Axle, rear assembly (5.38 to 1 ratio) (W/Powr Lok differential)

NOTE: the previous axle number is no longer listed.
The term "involute" is used to describe the splines of the current standard axle for model CJ-3B.
We see that a seperate (optional) "Powr Lok" axle is now available.
Via numerical sequecing I KNOW that the current part numbers were issued just before this book was published.
The highest part number recorded in this publication is # 913389.

Jeep Universal Parts List CJ-3B CJ-5 CJ-6
Willys Motors, Inc. Issued June 1959
Group 21-03 Differential Rear Axle
NOTE: Up to Serial # 57348-33148 (CJ-3B)
...........................# 57548-43843 (CJ-5)
...........................# 57748-11871 (CJ-6)
..........After Serial # 57348-33147 (CJ-3B)
...........................# 57548-43842 (CJ-5)
...........................# 57748-11870 (CJ-6)

NOTE: The Group Index.
The following information is specifically concerning rear differentials.
We see that a change occurred in the rear differentials.
The serial plate numbers are provided.
I will now take you to the model CJ-3B Serial Number and Engine Number List.
http://www.film.queensu.ca/CJ3B/SerialNos/SerialNosEngine.html
When we scroll down to Serial # 57348-33148 (CJ-3B) we see that particular jeep is identified as very late 1956 model.

 

You can get a 19 spline Detroit Locker, but it won't fit with the two piece axles.