FC Explorer 8.8 Diff Kit

[theantirotor]

I will try to find a thinner nut then.  The nut that comes with the axle is a flanged nut with a washer built in also but maybe its not the same as yours.  I will probably go ahead and give these a shot.

[ebdyguy]

In case anyone is interested in using these CVs for their swap, I did a dimension comparison of a TII CV and one of the GKN CVs for a Mazda 626 Turbo.  I assume that it is the same CV that was shown as part of the complete 626 axle assembly shown by the OP.  The number stamped on the separate CV joint is:

  GKN  A8C151120196004  0006   

Here are the measurements in inches with the map in one of the attached pics

Dim   TII      626 Turbo
A   3.520      3.562
B   2.288      2.204
C   1.179      1.179
D   22mm x 1.0   22 mm x 1.5
E   .430      .390
F   .511      .509   
G   2.724      2.477
H   4.061      3.660
I   2.469      2.520
J   1.337      1.183

The dimensions of concern are G & J.  The overall engagement of the spline will be ~.25” less when using the 626 CV in the RX7 hub.  Since the spline length in the hub is approx. 1.43” which is nearly fully engaged with the TII CV the engagement length will be approximately 1.18”.  That may cause some concern by some.  The shorter length of the threaded section seems to be accounted for with the overall shorter height of the combined washer/nut that comes with the axle.

On a side note, since the pitch of the 626 axle thread is courser than the TII thread some minor adjustment of the tightening torque value might be in order – but probably not that critical.

Hope that helps anybody that might be considering this CV for their swap.

[MoparX]

I know the cradle was designed to work around the stock Explorer breather, but it was broken on my diff.  I was looking for a solution (like the air tool breather idea) and came up with a way to re-use the stock breather from my N/A diff.  It was simple and hopefully this will help others who run into the same problem.

Stock breather from N/A diff.  14mm socket to remove it.


The plastic sleeve in the Explorer diff.  I removed it, trimmed the top to make it flat, and used a 9/32" drill bit to open it up enough to screw in the new breather.  If a 9/32" bit isn't available a 5/16" would probably work.


After screwing in the Mazda breather.  This works on the same concept as drywall anchors and is very snug.


Just a little grinding to clear.


Installed and ready to go.  Lots of clearance, just hard to see in the pics.






Pay no attention to my hacked up diff cover.  It'll be cleaned up when I rebuild the unit.

[largeorangefont]

Be careful because that remaining plastic piece in the diff cover that you screwed the vent into can easily come out of the diff cover. Mine was aluminium not plastic, and I pushed it out with a screwdriver and a very light tap with a hammer.

My setup is not for everyone, but I removed the stock nipple and tapped the cover for 1/4 NPT. I used a 1/4 male NPT to 3/8" hose barb 90 degree fitting. I will be running 3/8" hose to a catch can. You could run a short length of hose and just put a filter in the end of the hose as well.

[MoparX]

No it's more of a pressed fit, like a drywall or concrete anchor.  You know, like one of these....



I know what you mean about it pulling out (I had to put it in my vice to drill it), but when I screwed in the breather it expanded the plastic tight against the bore.  I tried to pull it out, it's not going anywhere.

[largeorangefont]

Here is the Ford axle vent. I don't remember the thread pitch off the top of my head though.



http://www.latemodelrestoration.com/item/LRS-4022A/86-04-Mustang-88-Rear-Axle-Housing-Vent

[frijolee]

The problem with the short breathers solutions is that they'll still spit a bit of fluid (or at least Charlie's did).  Running a hose out and upward is the preferred solution because it lets any fluid run back into the diff if it gets in the hose in the first place.

[largeorangefont]

The problem with the short breathers solutions is that they'll still spit a bit of fluid (or at least Charlie's did).  Running a hose out and upward is the preferred solution because it lets any fluid run back into the diff if it gets in the hose in the first place.

Agreed. The Explorer cover's lack of internal baffling can make a mess.

There is a TSB part for the Boss Mustang that may be helpful here. We could probably use this with a couple brass 90 fittings, and thread this part into it.

It is called the Turkey Baster, and is designed to collect small amounts of diff fluid and incorporates a vent. Ford part # AR3Z-4A058-B


It is designed to be use on the 8.8 axle tube and threads in but can also be used on the diff cover.

[gc3]

wow i wonder why they call it a turkey baster

[Bowtie7]

Ford uses a long hose on the Explorer cover. I did not know that originally and set up my vent like a Mazda diff cover. It didn't piss all over the place but there was definitely a good "misting" of gear oil all over the place after I got back from SNS 2011. I have since fitted a long tube to the cover and run it up and over to the left rear with a small rubber elbow on the end. Problem solved 100%.

I think that any of these that are hitting the track should consider long hose and vented catch can at least until we know how everything behaves when the diff temps are higher than street temps. Remember that Ford recommends 75w140 fluid. There is a factory TSB about it.

[DeaconBlue]

I think that any of these that are hitting the track should consider long hose and vented catch can at least until we know how everything behaves when the diff temps are higher than street temps. Remember that Ford recommends 75w140 fluid. There is a factory TSB about it.

Remember that the 75w-140 gear lub is for the factory clutch pack type Track Lock LSD.  If you switch to a gear type Eaton True Trac or Torsen LSD, then you can use 75w-90 gear lube.  High horse power or track only cars may want/need to look into a differential fluid cooler setup as they will be working their LSD pretty hard.

Also there was a TSB issue concerning the Explorer IRS 8.8 and gear whine - apparently they were note setup 100% correctly during assembly - hence the TBS about the switch to 75w-140 gear lub.  Check with a local Mustang shop in your area that has experience with working on and setting up the Mustang Cobra IRS 8.8 differentials.  It would be best to get the unit checked out or rebuilt and setup better than what the factory had done prior to installing it in your RX7.  Also since this is an aluminum case 8.8 IRS, if you are changing gears or LSD types, you will need special tool(s) to get the preset right for the proper bearing pre-load.  That is something the folks with the iron case T-bird 8.8 IRS or 8.8 stick axle folks don't have to worry about.

[MXJS]

I just read through the entire thread and I'm really considering one of these over a granny's solid axle.  I would like to see some results from a car with bias ply tires first.  Right now my car dead hooks with the TII diff and I have never had it wheel hop, I just need to change the gear ratio.  So maybe this will work well for me.

[MoparX]

Finally some progress.




I do have a couple questions though.  The first is regarding the crown caps and whether or not it would be ok for me to flip them to gain some clearance.  I'm running Mazda Comp bushings, don't know if that matters.  The second question is whether or not it looks like my pinion flange is lined up correctly.  I think it's fine, the cradle is straight and the front mount lined up where it was supposed to, but my buddy thinks we messed up. 

[frijolee]

Crown caps: the simplest thing to do is to put them in a press and flatten them by about 1/4".  Then trim the tips of the "crown points" to match.

Pinion looks correct.  The subframe is not symmetric so we place the diff such that the halfshafts are centered.  We measured this several different ways so I'm pretty sure it's right even though it will be offset vs the dip in the subframe.

-Joel

PS:  we have several kits in stock if others are ready to order.

[MoparX]

Cool, thanks.