Forum Home Forum Home > CJ-2A Discussion Area > Tech Questions and Answers
  New Posts New Posts RSS Feed - Power-Lok limited slip in Dana 25
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Power-Lok limited slip in Dana 25

 Post Reply Post Reply Page  12>
Author
Message
bobevans View Drop Down
Member
Member
Avatar

Joined: 31 July 2005
Location: Pittsburgh, PA
Status: Offline
Points: 421
Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Topic: Power-Lok limited slip in Dana 25
    Posted: 11 Dec. 2018 at 9:53pm
So I got  Power lock differential from QTM on eBay and now it’s time to try and get it installed.  It’s anNOS part that has been sitting on a shelf for a couple of decades.  Packaging looked pretty good, but when I tore open the aluminum foil “bag” it was packed in, a lot of surface rust was evident.  I have cleaned it up with a wire wheel in the photo.  Luckily the clutches were perfect in oil

Edited by bobevans - 11 Dec. 2018 at 9:57pm

'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
Back to Top
Stev View Drop Down
Member
Member

Sponsor Member

Joined: 27 July 2016
Location: Cincinnati
Status: Offline
Points: 1282
Post Options Post Options   Thanks (0) Thanks(0)   Quote Stev Quote  Post ReplyReply Direct Link To This Post Posted: 11 Dec. 2018 at 10:03pm
Bob,

Is this th Powerlok for a Dana 25 or a Dana 27 - assuming you are putting it in Dana 25?

If it is for the Dana 27 you will need the spacer from Herm to make it fit properly in the Dana 25.  The spacer goes between the ring gear and the Power lock case.

Stev
Stev
1946 CJ2A Trail Jeep, 1948 CJ2A Lefty Restored
Back to Top
bobevans View Drop Down
Member
Member
Avatar

Joined: 31 July 2005
Location: Pittsburgh, PA
Status: Offline
Points: 421
Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 11 Dec. 2018 at 10:06pm
I got the kit to convert this Powr-lok, which is intended for the Dana 27, to use in my Dana 25 front axle.  The kit came Herm the Overdrive guy.  It consists of a new set of bearings for the carrier, a new pinion seal, carrier bearing shims, and an adapter plate that goes under the ring gear.  The plate is about 5/32"s thick and micrometer says .1568 thick.

Edited by bobevans - 13 Mar. 2019 at 10:26pm

'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
Back to Top
bobevans View Drop Down
Member
Member
Avatar

Joined: 31 July 2005
Location: Pittsburgh, PA
Status: Offline
Points: 421
Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 11 Dec. 2018 at 10:15pm
The carrier bearings in the kit seemed okay, but I couldn’t find the exact bearings from that source, so these are the equivalent Timken bearings.  I bought four cones and ground the insides of two of them to do my trial mock up for back lash and gear pattern.  You can see the trial bearings in the first picture.  I painted them orange so they don’t accidentally end up in the final product.  I will lightly sand off the paint in any contact area 

'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
Back to Top
bobevans View Drop Down
Member
Member
Avatar

Joined: 31 July 2005
Location: Pittsburgh, PA
Status: Offline
Points: 421
Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 11 Dec. 2018 at 10:22pm
First slight problem.  The thickness of the adapter is such that the original bolts don’t go very far into the carrier.  The bolts are 3/8 x 24 tpi and just about .8” long.  I found some ring gear bolts on Summit that are 1 1/4” long.  They were made for an Auburn limited slip for some long ago GM product and the metallurgy should be right since they are intended as ring gear bolts.  Here is a pic of how many threads are not engaged with stock D25 bolts

'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
Back to Top
bobevans View Drop Down
Member
Member
Avatar

Joined: 31 July 2005
Location: Pittsburgh, PA
Status: Offline
Points: 421
Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 11 Dec. 2018 at 10:25pm
Stev, you type way faster than I do!  You are a good bit of the inspiration for me doing this.

Edited by bobevans - 12 Dec. 2018 at 10:17pm

'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
Back to Top
bobevans View Drop Down
Member
Member
Avatar

Joined: 31 July 2005
Location: Pittsburgh, PA
Status: Offline
Points: 421
Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 15 Dec. 2018 at 9:09pm
Setting the backlash was challenging.  I had the whole shim stack on one side trying to get the ring gear away from the pinion and it wasn’t enough backlash, only about .003.  I took everything back apart and spent quite a lot time filing and cleaning up the carrier, the back side of the ring gear.  I also took the adapter plate and put some 600 and 1000 grit sandpaper on my jointer/planer table (probably the flattest surface I have) and spent about 1/2 hour flattening and ever so slightly thinning it.  After the massaging, I was able to get a couple of thin shims on the other side, get about.008 of backlash, and get an acceptable pattern.  It’s not perfect, but should be fine for a front axle.  The other bonus is I didn’t have to mess with the pinion.

'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
Back to Top
bobevans View Drop Down
Member
Member
Avatar

Joined: 31 July 2005
Location: Pittsburgh, PA
Status: Offline
Points: 421
Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 21 Dec. 2018 at 10:14pm
Got the bolts from Summit.  They are. 

'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
Back to Top
bobevans View Drop Down
Member
Member
Avatar

Joined: 31 July 2005
Location: Pittsburgh, PA
Status: Offline
Points: 421
Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 21 Dec. 2018 at 10:32pm
Lesson today, don’t be a big dummy.  Started putting everything back together.  All was going well until I put the last spindle in place.  It was probably at least 1/4” or more from seating and the axle was bound up tight.  I remember reading somewhere that someone had to grind the end of the axle.  The passenger side fit fine and that was side that had virtually no shim stack, so it should have been the tightest, but no it was the driver side.  I pulled the axle and ground off the end and added a little bevel.  Still no joy.  I decided I better take things back apart and check further.  Apparently when I was checking the plates/clutches for rust, one of gears that axle splines slid into got slightly rotated.  I loosened the carrier back up and slid it over one axle that I put in the vice, but this time I made sure I slid the other axle all the way down inside the carrier from the top and left them both in place until I got the carrier halves torqued back down.   So what should have taken an hour or so in the morning ended up taking all day and I have a slightly shorter axle now!


'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
Back to Top
bobevans View Drop Down
Member
Member
Avatar

Joined: 31 July 2005
Location: Pittsburgh, PA
Status: Offline
Points: 421
Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 24 Dec. 2018 at 12:05am
Some driving impressions. First, with the hubs locked and in the Jeep in 4wd, it is MUCH harder to turn. I did a little test at a parking lot near home. I did a parallel parking and tightest turning radius test.
Again difficult in 4 wd with hubs locked and largest turning radius.
Still somewhat difficult in 2wd with hubs locked.
Of course with hubs unlocked and in 2wd it turned normally.
The off-road course was behind my house in the field. This thing acted almost like a spool. It certainly drove both front tires, but the field is really soupy, so it's hard to say how it will act on solid ground.

I'm hoping it loosens up a little bit. I want some lock up, but as I was trying my parallel parking demo, I felt a little like the video of Stan getting some help from his passanger to turn the steering wheel!

'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
Back to Top
chasendeer View Drop Down
Member
Member


Joined: 23 Feb. 2012
Location: Napa,CA
Status: Offline
Points: 542
Post Options Post Options   Thanks (0) Thanks(0)   Quote chasendeer Quote  Post ReplyReply Direct Link To This Post Posted: 24 Dec. 2018 at 1:15am
That is how mine is also. Can’t turn it on dry pavement in 4wd.
Back to Top
Nothing Special View Drop Down
Member
Member
Avatar

Joined: 02 Feb. 2018
Location: Roseville, MN
Status: Offline
Points: 328
Post Options Post Options   Thanks (0) Thanks(0)   Quote Nothing Special Quote  Post ReplyReply Direct Link To This Post Posted: 24 Dec. 2018 at 8:02am
I hope you find a good happy medium.  And I know that options are limited for a Dana 25.  But that's my complaint with clutch-type limited slips (and why I'd never choose to have one).  They are too much like a spool when you don't want one and are too much like an open differential when you don't want that.
Bob

Flatfender wannabe
'71 Ford Bronco
Back to Top
bobevans View Drop Down
Member
Member
Avatar

Joined: 31 July 2005
Location: Pittsburgh, PA
Status: Offline
Points: 421
Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 24 Dec. 2018 at 4:10pm
I had a limited slip in the rear axle of my '79 CJ7 (1974 CJ axles) and I absolutely loved it.  It was well mannered on the road and off road it would jump in and help after I started spinning a tire.  Before a trip to the Rubicon I replaced it with a lunch box locker.  It works well, especially off road, but it pops under load in a turn and ratchets with no load (since I can't hear the ratcheting really doesn't bother me!).  Probably my biggest beef with it is when side-hilling.  If I hit a really slippery spot and both rear tires spin, the whole a$$ end slides down hill.

I'm gonna drive around some with the hubs locked and see if it doesn't loosen up a little bit.

'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
Back to Top
RICKG View Drop Down
Member
Member
Avatar

Joined: 08 Jan. 2015
Location: so idaho
Status: Offline
Points: 1519
Post Options Post Options   Thanks (0) Thanks(0)   Quote RICKG Quote  Post ReplyReply Direct Link To This Post Posted: 24 Dec. 2018 at 6:21pm
Originally posted by bobevans bobevans wrote:

I had a limited slip in the rear axle of my '79 CJ7 (1974 CJ axles) and I absolutely loved it.  It was well mannered on the road and off road it would jump in and help after I started spinning a tire.  Before a trip to the Rubicon I replaced it with a lunch box locker.  It works well, especially off road, but it pops under load in a turn and ratchets with no load (since I can't hear the ratcheting really doesn't bother me!).  Probably my biggest beef with it is when side-hilling.  If I hit a really slippery spot and both rear tires spin, the whole a$$ end slides down hill.

I'm gonna drive around some with the hubs locked and see if it doesn't loosen up a little bit.
 
And you added the LS friction mod additive to your GL-90 correct?
I never met a mule I didn't like!
MC51986 "OD MULE" DOD 01-52
Keep 'em Rollin'
Back to Top
Mark W. View Drop Down
Member
Member
Avatar

Joined: 09 Nov. 2014
Location: Silverton, OR
Status: Offline
Points: 4502
Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 24 Dec. 2018 at 8:29pm
yes do not forget the Additive
Chug A Lug
1948 2A Body Customized
1949 3A W/S
1957 CJ5 Frame Modified
Late 50's 134L 9.25"clutch T90A D18 (1.25") D44/30 flanged E-Locker D25 5.38 Since 1962
Back to Top
Mark W. View Drop Down
Member
Member
Avatar

Joined: 09 Nov. 2014
Location: Silverton, OR
Status: Offline
Points: 4502
Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 24 Dec. 2018 at 8:32pm
The behavior is why I chose to go with an E-Locker in the rear that I can control. Once I have CHUG completed and the aluminum top built and my Off road trailer then I am going to build either a DANA 30 enclosed Knuckle or a Dana 44 and put an E Locker in it. But I know that will end up costing more then my fancy rear axle did it comes last on the big plan.
Chug A Lug
1948 2A Body Customized
1949 3A W/S
1957 CJ5 Frame Modified
Late 50's 134L 9.25"clutch T90A D18 (1.25") D44/30 flanged E-Locker D25 5.38 Since 1962
Back to Top
nivrat View Drop Down
Member
Member
Avatar

Joined: 27 May 2014
Location: Glendale, AZ.
Status: Offline
Points: 83
Post Options Post Options   Thanks (0) Thanks(0)   Quote nivrat Quote  Post ReplyReply Direct Link To This Post Posted: 25 Dec. 2018 at 1:15pm
The clutches will loosen up over time with use Bob. The other thing you can do is to change the order of the clutches to make it a little less aggressive.

FWIW,
Mike
Back to Top
bobevans View Drop Down
Member
Member
Avatar

Joined: 31 July 2005
Location: Pittsburgh, PA
Status: Offline
Points: 421
Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 25 Dec. 2018 at 2:08pm
Thanks for all the input.  I did add friction modifier to the lube.  If they don't loosen up some I will try rearranging the clutches/discs.  Stev suggested a certain order and I've seen his Jeep work off road.  As I said earlier, his modification was one of the reasons I did mine. 

Mark, I would much rather have something selectable.  I have had a couple of Jeeps with ARBs and my current Rubicon has selectable lockers.  There just aren't a whole lot of options for the D25.

'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
Back to Top
 Post Reply Post Reply Page  12>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.01
Copyright ©2001-2018 Web Wiz Ltd.