[Tyler-98-W68]

I figured I'd start a new thread to highlight the progress and the successful attempt (or failure) to get some sort of locking differential made up for my Compass.

Reason:

As I've explained before the BLD function of the MK's works well offroad but with limited torque available sometimes the BLD causes the vehicle to bog out and lose forward momentum. If a mechanical device in the differential could transfer torque across the rear axle without as much loss in torque from the brakes being used I feel the MK's would gain a lot more capability offroad.

Complications:

I have looked high and low for information on the rear diff in our MK's and while Aroundincirlces found a place that lists out rear diff being a Chrysler 8.25"
http://www.ringpinion.com/b2c/DiffL.../b2c/DiffList.aspx?SearchMode=Make&MakeID=7&ModelID=514&Side=Rear&DriveType=4WD

Looking at the specifications I can't see it as really fitting, otherwise someone would have done it already!

I"ve also never been able to track down any interior pictures of the MK diff, as I will need to take the diff apart to measure all the spider gears pinion ect.

Here's what I have found so far, the mitusibish outlander (The newest ones) use the same differential as MK's I've established that by looking at ebay auctions for them and the diff is exactly the same as ours. The main difference being is gearing.

Since I have a FDII compass, the rear gear ratio is 8:1, which is incredibly low and I think this may ultimately limit my chances at getting a locker or something put it.

What I've done so far:

Purchased a used differential out of a 2009 Patriot FDII with 37000kms on it. Basically the same mileage. Still waiting for it to be shipped out to me.

Cross Pin diameter = 0.587"

Spider Gear Hole diameter = 0.592"

As you can see it looks like a "normal" differential

 

[Tyler-98-W68]

As am I, lol i'm hoping I don't run into the problem of not having a standard size ring and pinion gear, time will tell!

 

[Tyler-98-W68]

The diff should be here early next week I hope. Unfortunately I had surgery on my foot a few weeks back so my mobility is reduced but by the time the diff gets here I should be able to walk without too much trouble, it's not a huge issue as I have someone to work on my diff anyways.

Doing some thinking and pretending for a second that there is lockers available, i'm torn at what I want to do.

ARB air locker is at the top of my list for a few reasons:

It's a totally seamless operation functioning like an open diff until needing to lock it up.

Problem is i'm looking at nearly $1500 to get the locker, air compressor and everything else needed to make it work. It seems rather complex and there could be things that go wrong with it.

Powertrax No Slip

I"ve looked a lot at these and watched videos, it seems that they are rather street friendly and will unlock going around corners on the street. I could get one for around $500 so money wise it's attractive.

Looking at it from a traction control perspective I cant see any issues with the operation of the BLD or traction control since both tires will always be spinning at the same rate (except when turning) in reality the BLD will only be functioning on the front axle.

The downside to this is that I live in a climate where we have snow for 5-6 months out of the year and i'm thinking I might notice some extra back end slip going around corners while doing city driving on slippery roads, I might not have any problems as the traction control will probably compensate for that, and the fact that the rear end isn't going to be getting power all the time anyways unless I lock it in 4x4.

First things first though I have to determine whether a locker will actually work. The last ditch effort may be to weld it, but that creates it's own set of problems, mainly i'm not sure the back end components are strong enough to survive being locked while driving on the street. I could see the CV axles snapping like twigs, but I don't really know for sure.

Anyways I"ll post again when I have some more updates.

 

[Tyler-98-W68]

Diff has arrived!

Things to note, damn thing is a lot bigger off the vehicle and what pictures would suggest.

In the last picture you can see what I believe is the driveline vent, which apparently is higher on FDII modules. It looks like nothing more than a small rubber tube, that in theory could be extended and relocated to an ever higher position to increase water fording capability.

I have a couple emails out to a few companines regarding information on lockers and or LSD's hopefully I get some positive feedback soon.

 

[Tyler-98-W68]

Haha, it just showed up today i'm still not super mobile yet, I should have it open by the end of the week. So someone had just reposted that service manual in a thread, turns out there is complete pics on how to disassemble it.

By no means an accurate measurement but i'm going to venture a guess that the ring gear is 6.5-6.75"

Looking online a dana 28 diff, which was a front diff for the older rangers is 6.625" 23 spline Powertrax lists a lockrite for it, unfortunately they are less street friendly that the powertrax no slip lockers they sell.

I really hope something can be done, I would be 100% happy and content with my Compass at that point. I might even be finished modding it too.

If I was able to get a locker put in, I was thinking about putting one in my factory diff and possibly selling it to another member to offset the costs of the whole project

 

[Tyler-98-W68]

The evo diff while similar is different as a member here pointed out there is no spot for the ecc clutch to attach at the front of the diff like it does on the patriot. So I'm not sure if it would actually work. Sandstone that wavetrac diff looks ideal. I will email then today and see what they have to say.

 

[Tyler-98-W68]

From my limited searching it appears it is an LSD.

 

[Tyler-98-W68]

Well I emailed wavetrac and they got back to me very quickly.

Tyler, thank you for your inquiry, but unfortunately we do not have a unit available for your vehicle and there is no planned production for a Wavetrac application for that car at this time. Usually for us to start making a new production we would need enough interest to make a batch of 30-50 units if that information helps at all, we have not had any other inquiries on a diff for that vehicle that I am aware of.

So....do I buy 30 diffs and then resell them to everyone, too bad that's not cost effective in the least.

I'm not too deterred though since I highly doubt anything would be a ready to install product for our jeeps anyways.

 

[Tyler-98-W68]

So i'm typing this out in disbelief and I still can't quite believe it myself................a while back I emailed a company.

http://lokka.com/site/

I used their application guide and while they list a Compass as a option when filling out the form, it comes up with no fitment.

Last night I got this email:

Hi Tyler,
Thank-you for your enquiry about LOKKA automatic differential locker.

Have you tried the LOKKA 'Wizard' ?
Yes, there is a model LOKKA to suit your vehicle.
Use the 'Lokka Wizard':
Jeep
Compass
2012
Canada

The result is JEE-RO-152
Cost is $259 including shipping to your door.

If you wish to purchase, use the 'LOKKA Wizard', or if you have any further questions, please email.

Are you kidding meepper:epper:epper: Either they have existed the entire time or the made something up for me:notworthy:

I know its not a selectable locker which would have been the best idea, however the thought of zero modification to make this work is extremely appealing. If it turns out this actually works and a selectable locker does in fact exist I will have my existing factory diff I could add it too since I will have a spare laying around.

I will update with more info as I get it

 

[Tyler-98-W68]

I totally agree with you, when I emailed them a ways back I explained I had a jeep compass with a cvt with IRS and a rear ratio of 8:135:1. So maybe they did their homework this time? Who knows just waiting to hear back on what they have to say to the million questions I have.

 

[Tyler-98-W68]

I have sent another email with detailed pictures of my diff, so hopefully they are open to the idea they may be wrong.

AIC I emailed ring and pinion, and sent them pictures, they have not replied, and doubt they will.

 

[Tyler-98-W68]

Have not had a chance to take it apart yet, project for this week is redoing the wiring for my light bar, and putting a switch in to kill the abs system, while offroading (if needed). I'm doing that project tonight.

 

[Tyler-98-W68]

Few things, never did the abs kill switch as I couldn't quite figure out how to run the wires and still make it reversible, basically rather than splice wires like the JK guys do, I want to run something from the fuse box anyway that is for a different thread.

I did get the light bar mounted, and got my winch control mounted inside.

I got an email back from Lokka, they want to know the spline count for my axles, so without further ado (the pics suck)

23 Splines is what I count, so until I get the diff ripped apart I have this info to go on for now.

 

[Tyler-98-W68]

The moment we all have been waiting for, an MK rear diff exposed for the first time:wow:

So I measured the ring gear and it came out at exactly 6 inches. I suppose I might have to take the carrier out too, however that is far above my mechanical skills to try that so someone else will have to do that if it will be necessary.

The guy I've been dealing with from Lokka has been very helpful and I will be passing information I have gathered onto him. Since the part they originally thought would work was $259 shipped. Who here would be interested in an auto locker like this should something be made up. My theory is that if their was enough interest I might stand a better chance at getting something made up.

 

[Tyler-98-W68]

The difference in ring gears I think is

FDI 6.12:1
FDII 8.135:1

Now I can't be certain than something up front in the transmission might be a bit different I will take a look into that.

Ideally I would like a selectable locker however that is big money and I"d have trouble dropping about 1500 to get that all set up.

From my limited search online it seems the closest axle I could come up with, with specs like this one, is a Dana model 28 used as the front diff in ford Rangers in the 80's 6.625" ring gear 23 splin axles, c'mon .665" can't make that much difference can it.......i'm sure its worlds of difference though.

 

[Tyler-98-W68]

IF something could be made up, a locking diff in a FDI would make worlds of difference, no need to be swapping gears ect. Just waiting to hear back from Lokka

 

[Tyler-98-W68]

Good find, I don't have much to report so far as I need to find the time to get the entire diff ripped apart and send the measurements off to Lokka, but I hope to have that done by the end of July.

I will take a look into the Samurai diffs and see what I can find.

 

[Tyler-98-W68]

LOL no donations until its done (I have paypal).

Samurai ring gear = 6.9" so while small, it still is almost an inch larger in diameter than the MK's (6")

As for the ABS kill mod, I haven't done that yet but is on my list to have someone do it next week. It would be very simple to tap into the wiring in the cab and run a switch, however I want this mod to be totally reversible so that if I need warranty work I can turn it back to stock.

I suppose I should make a thread on my ideas for this mod as to not derail this thread.

I wish I was more mechanically inclined so I could get everything done sooner, but between my work schedule (on call 24/7) its tough to make plans with the individuals who are going to work on my vehicle.

I'm a firm believe that with the abs disabled and a locker in the rear, I should be able to do much more than before. The ABS switch idea might not be needed because in theory the only BLD that would be activating would be on the front axle, but i'd prefer to have all the engine power available and not being sucked away by brake applications.

 

[Tyler-98-W68]

I can't see any ill effects from switching it on and off while driving. To date I have always shut the vehicle off, then pulled the fuse. Same thing to replace it, turn off replace fuse. Thing is though its really only a fuse and a fuse can blow during operation shouldn't hurt anything.

When I do put the fuse back in, it takes about 20 seconds of forward movement for all the lights to go out and return to normal operation.

 

[Tyler-98-W68]

Did you mean I should rename it to Locking diff + ABS kill mod?

As for the wheel spin work around, I do the same thing by cycling in and out of the FDII mode to create wheel spin, then lock it back in 4x4. It works good in some cases where I've tried it.