ctross

So, I finally made up my mind to go with 4.10's (took long enough) and was about to place the order when a suggested product in the sidebar caught my eye and made me think.

This might be a total newb question, but better safe than sorry, right?

A higher gear ratio is going to make my drive shaft spin more per tire rotation correct? So, does that mean the drive shaft will fail at an earlier speed than the 130-140 range its already known to buckle at because it'll be spinning faster earlier?

I dont plan on removing the governor with the tune after install, but I occasionly like to take the car up to about 110 when im the only one on the freeway.

Does anyone have experience with 4.10's in their 4.0 at high speeds? Should I wait till I can get an alumimnum driveshat?

pascal

I'd be more worry about your differential (7.5 POS) than the drive shaft.
Did you just change gears or improved the whole thing like T-lock as well?

ctross

Thats another thing I considered.

I was going to just purchase an 8.8 with 3.73's since it'd come with a LSD, but didnt think the 7.5 was something to worry about until I actually start adding power. Realisticly I dont think i'll ever get to boost the 4.0 in any way and was always under the impression the rear end would handle simple bolt-ons just fine.

But yes if I purchase the 4.10's for the 7.5, I will also be buying a LSD.

now Im worried about both though which raises another question ahah

JimC

All it took on my 7.5 to break it was a tune, CAI, and drag radials. I tried to build up the 7.5 with tlok, 3.73's, and a LPW girdle to handle it. Bent the pinion on a set of allegedly indestructible Richmond gears the first summer after doing the upgrade.In the end it cost more to build the 7.5 than it cost me to buy a take off 8.8 and swap it.

ctross

Good enough for me, I'll spend a couple extra hundred on the 8.8.

Something is telling me 4.0's just really arent meant to handle much, but I'd really like to avoid dropping $500-$700 on a driveshaft if I dont HAVE to. I'll eventually get an aluminum one, just dying to upgrade my gears asap.

Stang-aholic

an 8.8 swap is the best thing to do. Many upgrade the 7.5, but it always ends up costing about the same (or a little less) than an 8.8, but having an 8.8 will give you better piece of mind plus its always there down the road if boost/nos/slicks etc. come into play!!

ctross

Peace of mind is all I need. Don't ever want to have to worry if my upgrade is going to damage my car, which is why this driveshaft is bothering me. The horror stories that are out there..yikes! I dont want to be in constant fear that if I go just a little too fast its going to shoot up through the floor

Stang-aholic

well... with 4.10s in a 8.8 vs a 7.5, the risk of blowing up the drive shaft stays the same (with reference to RPM of the driveshaft). Ive taken mine up to 120/130ish with 3.73s and it vibrates like crazy (my wheels are **** too, new ones on order..) but ive only done this maybe 4 times its whole life..

I'd say thats the limit, so if 110 is what you'll be doing every-once-in-a-bluemoon, I'd say its OK... but a new DS is next on my list after brakes (another good idea if 110mph is in your driving pattern)

ctross

Already made the invesment for good brakes and tires! 3.73's at that speed make me feel a little better, but pretty sure I'm going to be getting a DS sooner than I planned. Thanks for the insight!

Stang-aholic

just make sure your rear tire size diameter doesn't decrease less than 27" (along with your 4.10's) or you could be looking at the equivalent of 4.30's at high speed with a stock DS will raise concern!

No prob! I wish I woulda gone with 4.10s and increased my rear tire diameter! so 4.10s acted more like 3.90s and I got the looks of a fatty out back.... but maybe thats later haha!!