Here is all the info in one place.

1. Most 8.8s considered for this swap have the same cover, so pick the one you want.
2. You can get an Iron or Aluminum differential case.
3. 99 Cobra's have a 28 Spline carrier. 01,03-04 had 31
4. The factory carrier that comes in the T-Birds and Mark 8's is a 28 spline unit.
5. You want a 31 spline for the true Trac.
6. The 8.8s IRS are found in the following vehicles:

1989-1997 Thunderbird Supercoupe (SC)(All Posi)
1992-1997 Thunderbird V-8 models with rear disc brakes(some posi)
1992-1997 Lincoln Mark VIII (All al carrier, most non-posi-traction)
1989-1992 Mercury Cougar XR7, supercharged V-6 (All posi)
1993-1997 MC V-8 with rear disc brakes(some posi), after 94 all Cougs were XR7’s

Cover Bolts: 10
Ring gear diameter: 8.8”
Pinion shaft diameter/splines: 1.625/28
Axle shaft diameter/splines: 1.29/28 or 1.32/31
Available ratios: 2.26, 2.47, 2.73, 3.08, 3.27, 3.45, 3.55, 3.73, 3.90, 4.10, 4.30, 4.56, 4.88, 5.13, 5.71, 6.14

Quote Originally Posted by punishmentcycle View Post
54, just for the list.. f150's,explorers,expeditions etc have 31 spline carriers. some are posi some are not. gotta check the tags on the housings
7. Gear Ratios:

3.08 3.27 3.31 3.55 3.73 4.11 4.30 4.56 4.88 5.13 5.71

8. With the CS kit, you do NOT need to modify exhaust on stock exhaust. Magnaflow and B&B need to be dimpled on one side.

9. Quiet Gears = Ford Racing A-4209-88373 or M-4209-88373 (3.73s)
10. Best diff = Ford Racing A-4204-F318 with carbon fiber clutch plates

11. To determine the gear ratio, and whether or not the unit has posi-traction, look at the tag that is attached to one of the differential cover bolts.

The first 4 spaces signify the gear ratio and whether or not it has posi-traction.
If the unit has posi-traction, then the second space will have an L in it representing (limited slip), the remaining spaces specify the gear ratio.

For example, 2 L 7 3 means posi-traction with a 2.73:1 gear ratio. Most people pay a salvage yard between $300-$400 for the donor parts.

12. Creative Steel 8.8 Diff Swap Fastener List:

Driveline adapter to transmission yoke -
• 3- 12mm x 35mm(1 3/8") socket-head cap screws (allen wrench)
• 3- 12mm all metal lock nuts

Driveline to adapter -
• 4- 10mm x 25mm(1") socket-head cap screws(allen wrench)
• 4- 10mm lock washers

Carrier bearing to carrier bearing bracket-
• 2- 8mm x 15mm(1/2") hex head bolts (may already be installed)
• 2- 8mm lock washers (may already be installed)
(Use original bolts to bolt carrier bearing bracket to car)

Driveline to differential yoke-
• 4- 12mm x 25mm(1") 12-point bolts

Differential to sub-frame-
• 2- 14mm nuts
• 2- 14mm lock washers
(Use original bolts in all three mounting locations. use the two supplied 14mm nuts on the bolts that go through the rear differential bracket)

Torque specs-
8mm- 15-20 ft lbs 10mm- 40-45 ft lbs 12mm- hex 55-60 ft lbs 14mm- 65-70 ft
lbs
12mm- cap screw 60-65 ft lbs

** Use supplied Loctite on all fasteners for added safety**

13. Install Videos are nice:


14. DIYrs will need the Diff front mounting bushings.

15. Some Eaton True-Trac carriers "clunk" straight out of the box.

16. mpsautosalvage on Ebay seems to be a popular place to buy used diffs.

17. Prothane front poly bushings: http://www.summitracing.com/parts/PTP-6-1609/

18. Modifying the rear cover: https://ls1tech.com/forums/cadillac-...ver-8-8-a.html

19. Diff breather vent at summit part # SUM-E730311

20. Front Bushing size, with picture: https://ls1tech.com/forums/cadillac-...ings-diff.html

21. When removing stock CVs, pull back the boot and remove the Snap Ring with a pair of Snap Ring pliers. The CV will slide off now. No Vise or hammer needed.

22. It is advisable to drill and tap a hole at the lowest point in the diff housing to aid in draining.

23. Aluminum front bushings: http://www.fortesparts.com/product_i...oducts_id=2984

24. 8.8 Gear swap with photos: http://www.kitcarinfo.com/IRS_Gear_Swap.htm

LINKs:

Used R&P from Randy's

http://www.ringpinion.com/b2c/PartsL...D=310&CatID=35

Rebuild
http://www.kitcarinfo.com/IRS_Gear_Swap.htm
For those interested in building their own diff, here is a 'DIY' for rebuilding the 8.8.
http://forums.bimmerforums.com/forum...0#post26742370

Gear Ratios
http://www.fordification.com/tech/rearends_ford13.htm

New Housings:
http://www.fordracingpartsdirect.com.../m-4010-g3.htm
http://www.race-mart.com/Ford_Motors...-4010-A88.html

Homemade 8.8 Case spreader:
http://www.svtperformance.com/forums...g-fixture.html

If you are using OEM Ford gears, be aware they are now made by Face Hobbing so adjusting the pattern is a little bit different than the older gears or aftermarket gears. These are what I used for reference when adjusting the pattern
http://www2.dana.com/pdf/5717.pdf
http://departments.weber.edu/automot...rpretation.pdf

Finally, I highly recommend going with a solid pinion spacer in place of the crush collar. I went with the kit made by Yukon. Ratech also makes one.
http://www.ratechmfg.com/fordspbs.htm
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25. Driveshaft shop quote on the CS kit......

26. OEM Vent: http://www.breezeautomotive.com/deta...=478&cat_id=13

 

Haha... I like this thread already. If we could source a good deal on axles and a driveshaft, a good source of 8.8 pumpkins and only have to use CS brackets, I'd be in for the cheap-o way of getting the 8.8.

 

Can you buy the CS brackets for 500 and use stock axles and Drive shaft with adapter?

 

the ds would be fine but the stock cv's are the problem..they are pure junk

 

Welcome *******!

I am too busy to source right now, but wanted this to get up here , so when people add GOOD info, I can compile for the community.

Like I said in the other thread, I am really open to fab up brackets and collect some pumpkins and start making a DIY kinda thing......

 

Just for budgets sake can you run a 8.8 cobra irs diff with stock cv's/axles and drive shaft with adapter? I am thinking about buying a 8.8 and the CS brackets with DS adapter for now then upgrading as I go along. I would upgrade the DS and cv/axles later. I Need to stop the whining from this BS GM diff.

 

Why would you want to run stock CV's and axles with an 8.8? You're not solving anything by just upgrading the differential.

 

Power is not the issue, reliability is for now. Then as the budget grows I can add the DS and cv/axles. I cant stand the whining anymore and I am not buying another crap diff.

 

I am going to go Sunday to pick up a complete 04 rear cradle with updated rear diff, axles, everything. I just picked up a plasma cutter today. I have a 8.8 center section out of a Lincoln Mark VIII. I have access to a brake that can bend 3/8 in small widths. I am going to give it a go trying to make my own brackets although it would be nice if someone would trace one for me. I think the hardest part will be to get the mounting positions correct.

 

There are a ton of people who have cracked the diff without hurting an axle. Would it be my choice to put stock axles in with an 8.8........no, but for budget friendly people who can add better parts as they go I dont think its that bad of an idea.

BTW I know as good as most that I never have the money to throw 4k down on a modification at once, and being able to spend 1000 here, 1500 here is much more manageable.

 

I agree, and especially for NA non-stroked guys, though I would go with at least one anti-wheelhop axle.

 

Well, in that case, I think obstacle #1 is establishing a parts list. I know a couple of things about how a 8.8 fits together, but I'd hope to hear from someone who knows exactly how a 8.8 fits together.

The #2 obstacle is mocking up a bracket similar to the Creative Steel model.

 

I think we're gonna need
1: 8.8 Rear diff
2: Inner CV joints
3: Coupler to attach 8.8 to stock drive shaft (which possibly needs shortened)
4: Brackets to mount 8.8 in car
5: Modified rear cover (I'll do my own)

 

Another reason to ditch the stock shaft. What I meant earlier was that we need a 8.8 parts list: things like the ring and pinion, the differential, etc.

 

U need a 8.8 31 spline locker type carrier,ring and pinion of ur choice, bearing/seal and install kit with shims, axle bearings and seals. That would take care of the pumpkin.

I actually just set my pumpkin up but I'm waiting on parts from CS. So far I got my DS,and axles but they sent me axles without the outer CV'S that I paid for!! So ill be waiting for those outters plus I still haven't got the brackets or hardware yet I'm waiting on those too. Figures I'd be one of the guys who gets a messed up order

 

Right, but there are specific parts that are better than others, and it's anyone's guess as to whether or not the bracket that Creative Steel fabricated will work on just any 8.8", 10 bolt case and cover. Here are the three parts I've selected thus far:

http://www.fordracingparts.com/parts...KeyField=13180 ($100 on Jegs and Summit)

http://www.summitracing.com/parts/DTL-913A561/?rtype=10

http://www.summitracing.com/parts/MGR-F888355/

Apparently, Motive ring and pinion sets are machined straighter than Ford ring and pinion sets (here's the Ford option), which, if you understand how these gears work, results in a stronger, more efficient transfer of force but more whine. So you have a decision to make here: strength and efficiency, or whine. Internal misalignment (e.g. improperly shimmed gears or poor tolerances during manufacturing) will apparently exacerbate whine as well.

Also, note that I'm definitely dropping down to 3.55 gears. My goal is to increase the amount of time that I'm in 4th (1:1...the most efficient gear in the transmission) based on the speeds that I drive, and make 1st a little more controllable. Should pay off once I'm making over 600 RWHP.

 

I went 3.55's myself. Gears are gears.. Ford racing or any other good gear company. I'd be more worried about the clutch packs which I switched over the the cobra carbon plates. As far as covers go I picked up a cover with the girdle braces built in.. Can't modify it till I get the brackets but I honestly think I won't have to touch the cover. There are 100 different covers out there so that's a trial and error thing.

 

By the way the brackets will fit any 8.8 even a solid axle. All 10 bolts have the same cover pattern. All IRS pumpkins have the same front mount.. The solid doesn't. As far as whine, it's all in the setup of the bearings and shims. Guys who complain about while from an 8.8 set it up wrong or wore a pinion bearing,carrier etc.

 

I'm completely new to this. Could you explain what you said there?

For instance, aren't clutch packs a feature of our transmissions? How do they relate to the differential?

What are girdle braces?

 

I updated Post #1 with facts.

IF those facts are wrong, let me know.

And post pictures.