Advice on 03 IRS install in 99 Cobra

[ncitguy]

Need advice on the best way to bolt up the drive shaft of a 99 Cobra to a 03 Cobra IRS. Do I just swap differential pinion flanges, or buy an 03 u-joint yoke?

 

[cmefly]

The best way is to buy a 03 driveshaft rear flange from ford for about $35.00 and buy a conversion u joint part # percision 448 from napa or autozone. or you will need to change the differential pinion flange to the 99/01 style.

 

[gmsux]

I'd just swap the pinion flanges. much easier.

 

[birdman941]

I'd just swap the pinion flanges. much easier.

Yep.

 

[cmefly]

I am not sure how it is easier when it only takes 15 minutes to change a u joint. But if you do change the pinion flange just be carefull to not over tighten the pinion nut or you will change the preload unless you have a solid shim and not the factory crush sleeve. I have done it both ways with no problems.

 

[Jimmysidecarr]

I am not sure how it is easier when it only takes 15 minutes to change a u joint. But if you do change the pinion flange just be carefull to not over tighten the pinion nut or you will change the preload unless you have a solid shim and not the factory crush sleeve. I have done it both ways with no problems.

With air tools yes... with hand tools it takes a ridiculous amount of torque to further compress that crush sleeve. I don't think I would worry to much about that.

 

[v6mustang164]

The best way is to buy a 03 driveshaft rear flange from ford for about $35.00 and buy a conversion u joint part # percision 448 from napa or autozone. or you will need to change the differential pinion flange to the 99/01 style.

I did this about 2 or 3 weeks ago. It took less than 30 minutes to tap out the old u-joint and tap the new one in. Now if I put a t-56 the aluminum driveshaft will just bolt right on.:thumbsup:

 

[gmsux]

I did this about 2 or 3 weeks ago. It took less than 30 minutes to tap out the old u-joint and tap the new one in. Now if I put a t-56 the aluminum driveshaft will just bolt right on.:thumbsup:

Only if you have a T56, the yoke won't work with a T45/3650.

You don't want to compress the crush collar any more. Just use loctite on the pinion nut and make it tight. Use a punch through the flange to hold it. the U joint approach will be fine to but you'll have to spend $60 to do it.