I posted this on another message board...

[Deadguyllc]

But I'm still looking for answers! I went to install a 2415 powertrax locker, for a 10 spline Dana 44 rear axle, what I thought should be on my 1952 M38A1,and it doesn't fit inside the carrier. There are so many levels of paint on the axle, I can't make out any id on it. I have one for the Dana 25 front too, and that doesn't fit either. That rules of a Dana 41, 44, 27, and 25. Here are some pictures I took, can anyone help?

[Joe Gopan]

Your rear axle housing and Spicer ring gear number 18530 are the standard for the M-38A1 and CJ Jeeps of the period with the Spicer 44.

[Joe Gopan]

Some locking differentials are based on the axle ratio, is the one you bought intended for a 43 to 8 or 5.38 to 1 Ratio?

[Deadguyllc]

I didn't see that it was specific to any axle gearing, and my brief email contact with Powertrax tech support didn't bring that up. I emailed them back asking how I could tell I have the right locker. It says 2415 on the box, but I guess it's possible the wrong one was placed inside. Huge pain in the ass tho-that rear differential is not easy to take apart.

[Joe Gopan]

My guess is that they made an error. The axle tubing on one side or the other of the differential cover will have the Spicer spec numbers stamped into the axle tube. Perhaps that will help your vendor. Did you give them the "18530" Spicer Ring Gear number?

Crazy Guy on this forum may be able to give you some answers. He is into rock crawling mods.

[Deadguyllc]

I sent them all these photos. Maybe I should just ask them about sending the Lockright back to them. I bought it like a year ago from a vendor, I'm not sure now who the vendor was, but even so, I'll bet they would just send me to Powertrax anyways.

[Deadguyllc]

So, ran the numbers on the locker by Powertrax, and they say they are correct for a 2415 LR, which is the locker I am supposed to have. Gear ratio doesn't matter, and it is 10 spline. Everyone says it looks like a Dana 44, I replaced the back cover months ago with one for a Dana 44, but the locker doesn't fit in the carrier. Any help identifying this axle would be greatly appreciated.

[Joe Gopan]

Talk to them again, the axle in your pic is definitely a Spicer 44, the 18530 on the Ring Gear is part of Spicer Matched Gear Set SP-18528X which consists of one SP-18530 43 Tooth Ring Gear and one SP-11449 8 tooth Pinion Shaft.

2415 LR is definitely made for the Spicer 44, but not for the Spicer 44 as installed in the 50's M-38A1 and CJ-5 with the particular differential for those two Jeeps. The Later 50's and thru the late 60's CJ-5's were available with Power Lock from the factory and used a special case different from that of the one used in the earlier CJ-5 and M-38A1. They apparently do not make a kit for the case (Carrier type) as installed in your Jeep.
Either you did not tell them enough, or they did not ask the right questions.
The Power Lock CASE (Carrier) used for the 50's CJ-5 44 Axle appears to be Jeep Part No. 916775, and I believe the correct term for that case used for the 2415 LR Power Lock Kit is "Open Type".

916775 sold for $172.00 at the Jeep Dealers back in 1974

[Deadguyllc]

darn! That explains alot, thanks Ben. So, either an expensive replacement, or I am out of luck?

[Joe Gopan]

Don't know. Try Walcks and see what they say. The case you need splits apart. Power Lock was a Jeep factory item back then.

[Deadguyllc]

Thanks. I'll look around. All the distributors for Powertrax only say "Dana 44 with 10 spline axles. Fits M38A1". Nothing else. I bought their kit for my Dana 25 in the front, am I going to run into the same problem?

[Joe Gopan]

I have no idea.

[Deadguyllc]

Walcks had no idea. They had never even heard of the problem.

[Joe Gopan]

Take a look at the kit for the front, if it has the same features as the rear, it will not fit the front case either.

[Deadguyllc]

It is more or less the same. Do I need an open carrier for the front too?