4.10 gears + IRS = ?

when I had my 99 cobra I had 4.10's in it and had no problems at all. but I do suggest getting an irs brace and a few other things to firm up that irs so you wont get wheel hop.

yes like that one, I bought it for my 99 cobra but never installed it, bought it new for I think $78 but then sold the 99 and got a 03 so I didnt need it cause it comes stock on the 03.

Hey, whats up, I just got 4.10's installed in my 01 Cobra, I've had no problems so far, other than a tiny bit of gear whine. But I did buy the billetflow IRS Brace which cost $150, powder coated red, and I already had the Differential Brace (stock piece on an 03/04) installed before. Funny, I guess you could almost call both pieces the same thing, I've heard the differential brace referred to as the IRS brace and vice versa, anywho...go to billetflow.com, and the IRS brace on there is HIGHLY suggested if you're going to install 4.10's. the differential brace/irs brace (whatever you want to call it) is a stock piece on 03/04 cobras that you can buy from various places for rather cheap and goes nicely with new IRS Bushings and Differential Bushings. All this crap and I still have wheel hop. As for the drive shaft, I've heard you can buy the FRPP Aluminum Driveshaft, and have it shortened exactly 1 inch, and rebalanced for close to $75, haven't done that myself, but just what I've heard.

I'd check on the gear whine, my differential does no such thing. This could be due to improperly set gear lash. Great you've done all the IRS mods - get some drag radials and be done with it. I ran into the same deal doing all of the IRS mods. They help, but the drags finished it off perfectly - no more hop!