POWR-LOK Research

I just picked up a POWR-LOk for my Dana 27. Here's the required photo to keep everyone happy



I've been researching them for fun, both on the web and using the search function in these forums. On the web, the best resources I have found have been:

http://www.vernco.com/powr-lok/
http://www.film.queensu.ca/cj3B/Tech/SB500PowrLok.html

They both point to a good explanation of the powr-lok from Willys (Bulletin #500)



Way deep down in the dark recesses of the dana website, I also found found a description of the model 60 and model 70 POWR-LOK:

http://www2.dana.com/pdf/5315-3.pdf

It provides some more good information, and the following interesting text:

They go on to provide an example where they shift the discs and plates around to get less friction surfaces and a smoother feel (at the expense of traction performance).


I wanted to post this so others could find the information a little more easily.

I'll probably keep mine stock, but do any of you have any experience monkeying with the discs and plate arrangement?

Thanks,

Eric

 

Very cool that you posted that!

One of the old school tricks to make them more aggressive is to remove one of the flat plates on each side and replace it with another belleville plate (dished spring) of the same thickness to pre-load the plates more. Also, leaving out the friction modifier will cause the plates to grab tighter. They normally will chatter when they do slip and wear out quicker but it's an old drag strip trick that works ok.

 

Differentials By Jim Allen, (got it from randys ring and pinnion) has a section on rebuilding these power-locs and go in to detail on how to set up for diff amounts of lockup. well worth the $, great book. I can't figure out how to scan the page. Herm the over drive guy also sells rebuilt parts and new cross shafts for them as well.

 

Each powr lok has 2 pieces of information stamped on the case
1. build date
2. part number

based on the 2 powr loks I have, the part number for the Dana 27 is 22477X

I have one with a build date of 1/6/64 Shift A:




and one with a build date of 10/1/68 Shift B:

 

I'm always amazed at some of the quirks you find with some of the units.
I have seen regular hex head, 12 point, RH and LH thread bolts and cases.
not specific to D27 units, but all units in general.
I don't know if it's because they were built that way for a specific manufacturer, ie IH, Willys, etc, or more so about what they had on hand at the time.

 

That is interesting.

From what I can tell, the part number for a dana 44 Powr Lok should be 25564X. I'll verify this later in the spring when I take a look at mine.

 

here are some numbers from some 19 spline, D44 units I have :

3:73 22017X 2-18-0 A
3:73 23116X 12-9-68 A

reference only

 

This one appears to be a 30 spline count version.


There's a supersession list here:

http://www2.dana.com/pdf/X500-S.pdf

22017X=>23233X=>26988X=>73611X
23178X=>23116X

Not sure I'm reading it correctly, I would have thought the 19 spline dana 44 powr loks would have eventually mapped to the same part number.


For the build date of 2-18-0 A, do you think that is Feb 18, 2000? or maybe something didn't get stamped on the case correctly?

 

could be 60, 70 or even 80, who knows.
The 30 spline unit was never offered thru Jeep, as far as I know.
IH Scout 800s ( A or B ?) used flanged rear axles, 30 spline, I believe they were offered there.
over the years, you could find a 19 spline that was converted to 30 or visa versa.
the 3:92 D44 power lock I also have, the numbers aren't legible, very weak stampings.

Somewhere I had all the these numbers jotted down, for 25 thru 44.
I know that some Datsuns, Sunbeam (Tiger ?) or other makes had 44 powerlocks as well.

Some differences will include whether the crossshafts are drilled for spacers (tapered axles) or not (flanged axles). Lots of variables, but the number might help other decipher what they have or are looking at.

 

I was surprised to see them used in Volvos and Jaguars. In Britain, they are called the Salisbury/Thornton Powr Lok.

 

Back in the 90's I bought a rebuilt AMC 20 Powerlok from Hicks Jeep Shop in California. I was able to install it in my 80 CJ-5 but there was a little problem getting one of the axles to go back in straight. It wanted to enter the spider gear at a slight angle. I did manage to get it in though. After the installation and after I put the tires on, I tried to get the unit to slip but no luck and I figured that as I drove it, oil would find it's way between the friction discs. I took the Jeep for a test drive and I couldn't get the Powerlok to slip in turns. I made chalk marks on both rear tires at same positions and took it for a test drive on the pavement and did some firgure 8's on a paved parking lot and looked at the chalk marks on the tires. They were still lined up with each other. I could also hear and feel the tires scrubbing badly on the pavement and my springs making buckling sounds as the Jeep wanted to turn but the rearend wanted to go straight. I ended up pulling the Powerlok out. On closer examination, I could see that the case halves were bottoming out on the clutch plates, not on each other and that is the reason I had problems installing one of the axles shafts. The side gear was slightly miss-aligned because the case halves were out of alignment. When installing the ring gear, I did notice that the runout was out of tolerance. Essentially what I had was a spool. Turns out that Hicks had rebuilt it with Dana 44 friction discs. A call to Dana tech support revealed that the old AMC Powerloks required a different thickness disc.

 

I found an interesting document regarding the POWR-LOK on ebay. Here is the title page:



I scanned the whole document in pdf form, but I don't really have a good place to host it.

 

I've got a Powr-Lok for a dana 30 axle. It came out of an early Bronco. It'll be a couple of days but I'll get the numbers off it.

 

I still have my invoice for a new Powr Lok that I purchased in 8 / 84.
According to the invoice it is Spicer part # 21920X cost $295.00.
This one is specifically for the for the 3.92 thru 5.38 ratio, 19 spline model 44's.
I'm running 5.38's.

I also bought a new Powr Lok for my front model 25 Spicer axle.
Both units were installed using a W-99 pinion tool.

This Powr Lok will also fit the model 23-2 full floating rear axles as was used for the MB or GPW.
The cost for that Powr Lok was $ 225.00 in 7/84.

I have 80,000 miles on this set of front/ rear Powr Loks with zero problems.

I am not going to open my case just to read the Spicer part numbers.
But I can probably find the W/O # for most Jeep applications including the
Trac Loks if any one needs to know.

 

I have a pwr lok that I purchased for my D25 some time ago and would like to compare the numbers to it.

If there is any all inclusive listing for the various Jeep axles and ratio series it would be helpful for all.

 

I have one from a scout 44 with centered diff 3.73 gears and 30 spline. the numbers are
7 11 68 A 26846X
Ill sell it if anyones intrested

 

Powr Lok I just picked up fits the 19 spline model 44 axles with 3.92 through 5.38 ratios.
This one is dated 4-29 63 C Which means it must have originally been equiped with 4.27 ratio if it was from a CJ.
Spicer part # is 23181