Half Shafts

Dave, nearly 5 years ago I posted the information Of what I was running. Guess what I'm still running the Level 5 axles, set up as I posted. No failures In 5 Years. 1.44 60' times to date.

I did mention that I thought the stock 03-04 Cobra axles might work on the Mn12 cars. I've heard of several people running them since My post. You building a hybrid axle combining both is a great idea. The problem with it is the outer joint/stub shaft that goes into the hub. The same 28 spline outer shaft is the weak point. It will twist off after so many Hy torque dead hook launches. The upgraded 33 spline level 5 outer joint is the answer. But what do I Know, I'm just a V8 guy.

Good luck with your Project. ;)
 
Dave, nearly 5 years ago I posted the information Of what I was running. Guess what I'm still running the Level 5 axles, set up as I posted. No failures In 5 Years. 1.44 60' times to date.

I did mention that I thought the stock 03-04 Cobra axles might work on the Mn12 cars. I've heard of several people running them since My post. You building a hybrid axle combining both is a great idea. The problem with it is the outer joint/stub shaft that goes into the hub. The same 28 spline outer shaft is the weak point. It will twist off after so many Hy torque dead hook launches. The upgraded 33 spline level 5 outer joint is the answer. But what do I Know, I'm just a V8 guy.

Good luck with your Project. ;)

Mike, I am glad you posted because I just didn't understand what it was you were doing. So you are saying that all you did was adjust the boot and run the axles with less engagement in the socket? If that's it then maybe my concerns aren't legitimate.

I am often very skeptical about things when people say "it worked for me" because it only tends to work for them until - well - it doesn't. And then you never hear about it again.

My biggest concern about running less engagement was the chance that something came apart if the suspension went completely lax to it's end of travel, while at speed. This is the point of highest extension and is something that may never be encountered under normal driving conditions and certainly not at all under normal track conditions, but I suppose it could happen.

I thought from your description that you were somehow re-locating the actual tri-pod further out on the splines so as to increase engagement in the socket. That's where I got lost.
 
Dave the confusion comes from the fact I have been using the Drive Shaft Shop Level 5 axles. They are designed and assembled differently than the Stock Cobra axles. I was describing my custom assembley of those axles for use In my T-Bird application. I also did a second set that went into the now crushed black kenne bell bird I built for another T-Bird owner. Those axles are still in use on a very fast SC that you know of.

Again I wish you nothing but good luck on your project. :cool:
 
Level 5 axles in the middle of the install

We'll I've used the stock sir clip and drive the tripod out till the clip stops it but it still seems after test fitting with out the boot sealed up and balls on the tripod seem like there out closer to hanging out than I'm comfortable with, but it looks like it will work but seems if it was in another 3/8 of an inch it would be better, Mike do u remeber if the bearings on the tripod hung out of the inner joint I mean 3/4 of them are in, I just wanna be sure this is safe, I thought about calling the drive shaft shop to see if the had a longer shaft
Ps the outer 33 spline is huge

Robert
 
Robert, It has been along time ago since I assembled those Level 5 axles. I don't remember any issues with the tripod bearings not being fully engaged with the inner CV Joint. Check your assembled length, somewhere in this thread I listed the spec. Unless DDS has changed something, the two sets I built worked fine, and both sets are still in use. The only thing I ever had to do was check and retorque the axle nuts after each track session. Sometimes the lock nuts would back off slightly. But that's a good thing to check on any IRS axle.
 
Well the part that is engaged were it rides is fully engaged, just part ofte rollers on the tripod hangout like a 1/4 of them, if I could get a tad more I'd feel better but it may e more than enough
 
halfshaft setup

The swap over to 31 spline differential starts with aquiring your choice of trac lok or locker. I'm using a Detroit locker in my car. It is a little harsh for a street car. The Ford truck trac lok or the Auburn pro would be other choices, all of these are offered in 31 spline IRS compatable configuration. These diffs are a bolt in to the 8.8" IRS MN12,FN10,or Cobra housings. Good time to swap ratios too.

The next step is to chose your axle shaft. You will need a set of stock 03 Cobra axles even if you go with the DSS Level 5 shaft. This is because the Level 5's come minus the inner joint. http://www.driveshaftshop.com/MUSTANGC.V..ivnu
The link talks about having some inner cv's but that is old info and they can't supply the inner joint. If you watch the Mustang boards for GP's you can get these axles cheaper than the list price. I got mine through D'agostino Racing out of Florida.

To use the stock cobra axles (31 spline inner, 28 spline like the MN12 outer) It is just a matter of resetting the assembled length of the shaft as outlined in the Thunderbird or 99 Mustang shop manuals. The end to end length of a MN12 axle is 32.565" the end to end length of a Cobra axle is 32.190". The extra length comes from adjusting the plunge of the inner tri pod joint in the inner cv housing. The part number of the cobra axle is 2R3Z-4K138-AA.

To use the DSS Level 5's, it's a little more involved and more expensive as you need 2 sets of axles to make one. The beauty of these axles are the outer stub shafts. They are huge and 33 spline. They come with a custom hub and long ARP race studs. This forces you to convert to the Mustang bolt circle. The hub swap has been talked about many times so I'll not go into that.

The extra axle length is easily made up on these axles by the assembley process. The DSS axles use a external snap ring to retain the inner tri pod off the stock Cobra halfshaft. I did not use this, instead I assembled the inner tri pod just like stock using the internal ring and locking the tri pod all the way out on the shaft. The shop manual for the Thunderbird or 99 Mustang show this assembley.

From there it's a bolt in swap. I also did not use the axle lock nuts supplied by DSS. Instead I used the beefy stock Ford axle nuts that we normally use on the front spindles (the black ones) They torque down nice at 250 ft.lbs.

Any way that's what I'm running now.

Mike.........;)

I have my Mark VIII down in the shop now with the half shafts out of it. If I am reading your description correctly, the photo above number 9 in the attachment (97 TBird Shop Manual) shows the snap ring (part number 4K184) in question. It does look like there are two lands to choose from there about the right (5/8") distance apart, so this might just be possible. Otherwise, i am going to have to buy four axles and make two our of them. If you could add some clarification, I would sincerely appreciate it.

Monte
*98 Mark VIII
6sp TR-6060, 31 spline 4.10, lots of bracing, coil overs, delrin bushings
 

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I'm running the dss level 6 axles in mine and they were a direct fit. No modifications needed (besides swapping the hub obviously). I've put close to 10k miles on them so far with zero issues.
 

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I'm running the dss level 6 axles in mine and they were a direct fit. No modifications needed (besides swapping the hub obviously). I've put close to 10k miles on them so far with zero issues.
How long are they, how much engagement do you have and what kind of power are you running? I have the D'Agostinos for a cobra in mine and they have worked well up to this point. Now they do not.

Update: After looking at the DSS site, it appears that they actually make half shafts FOR the MN12. This is what I will use.

@AdamG thanks very very much for the heads up. that was way easier (if more expensive) than I thought it was going to be.
 
No problem. I'm not sure on the exact length but when I got them Bill and I compared them to a stock sc axle. Compressed they were the same length. However the dss axles have sliders at both sides so they would extend out over 2" further that the sc axles. The spline ends were the same length. I'm running around 500hp/500tq n/a, 363 stroker with a m5r2 transmission. I haven't had it on the track with the new axles yet but it gets driven pretty hard on the street. I broke a mark viii axle with my street tires last year and have definitely been a lot harder on it this year than when I had the old axles.
 
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