limited slip and 411 gears on my 04 v6.... | Ford Explorer Forums - Serious Explorations

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limited slip and 411 gears on my 04 v6....

86EXPLORER86

Well-Known Member
Joined
December 4, 2008
Messages
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City, State
SANTA CLARITA CA
Year, Model & Trim Level
FAST 2004 XLT 4.0 STRIPED
my local shop said

to make it posi and throw 411 gears its gona be 1200.


what do you think
 



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Is that for labor + parts? If so, that sounds about right cauz you'll need a new carrier in the back axle in addition to 2 gear sets and 2 master install kits. But ask them what sort of warranty they have on the install cauz not all "shops" know how to set up gears properly -- just so 1000 miles later you're not stuck on the side of a highway with a busted axle and have to shell out more cash.
 






yes this is in my truck out the door.

i think its gona be worth it

im checkn on the warranty
 






Sounds about right. The 8.8 IRS is a little easier to set up than its solid brethren, just because you can take it out of the chassis and put it on a bench to work on. And ya, make sure their is a warranty, our 3rd gen rears are very finicky, just make sure they set the backlash and pre-load to specs, I think they are different that the solid 8.8. What kind of limited slip are they giving you?
 






Does any one have this done yet to there 3rd gen


how much of a change ?????????????
 






4.11s seem kind of steep to me. Sure they didn't mean 4.10s?? Didn't know Ford had a 4.11 option for the 8.8.

I really find the 3.73s to be a nice choice with the V6.
 






4.11's and 4.10's are available for the 8.8. As long as the front and rear ratios are within 1% the vehicle works just fine on the road, and can even be as different as 2% and work just fine off-road with no side effects.
It just depends on the manufacturer. The reason for the very slight differences in axle ratios like 4.10 and 4.11 is because of the slight ring gear diameter difference between the front and rear axles. It's just not cost effective for the gear manufacturers to try and make the ratio exactly the same since that slight one-hundredth of an inch or so difference doesn't affect anything.
 






I am not aware of 4.11's for an 8.8. 4.10's for an 8.8 have 41 ring gear and 10 pinion gear teeth, the 4.11's for 9" fords have 37 ring gear teeth and 9 pinion gear teeth-nothing to do with the diameter.
 






I am not aware of 4.11's for an 8.8. 4.10's for an 8.8 have 41 ring gear and 10 pinion gear teeth, the 4.11's for 9" fords have 37 ring gear teeth and 9 pinion gear teeth-nothing to do with the diameter.
Actually ring and pinion ratio is all about diameter -- although not the outer diameter of the gears themselves but the contact area. The teeth is only a consequence of how to mesh the ring and pinion gears w/o having them slip past each other once torque is applied. The two gears could even be conic sections (that is imagine if they had no teeth) and it would still work but would probably slip due to torque. When we set up ring and pinion gears, we aim for a sweet spot between the "toe" and the "heel". The center of the contact pattern (which is dependant on the pinion depth) becomes the effective diameter of the ring gear, the rest of the ring gear towards the "toe" and the "heel", is dead weight. Counting the teeth and dividing is just an easy way to determine the approximate gear ratio, but you can very easily change the gear ratio slightly by changing the pinion depth -- which is why the difference between 4.11 and 4.10 is negligible after you factor in other fudge factors such as tire diameter due to wear, age (ring and pinion settings will change with use), tire pressure, weight distribution (which affects tire diameter), and so on. "Backlash" is then the margin of error between the teeth count and the effective diameters that the gears are using, allowing us to run a gear set that has been labeled 4.10 as really 4.097, 4.103, and so on.
 












Actually ring and pinion ratio is all about diameter -- although not the outer diameter of the gears themselves but the contact area. The teeth is only a consequence of how to mesh the ring and pinion gears w/o having them slip past each other once torque is applied. The two gears could even be conic sections (that is imagine if they had no teeth) and it would still work but would probably slip due to torque. When we set up ring and pinion gears, we aim for a sweet spot between the "toe" and the "heel". The center of the contact pattern (which is dependant on the pinion depth) becomes the effective diameter of the ring gear, the rest of the ring gear towards the "toe" and the "heel", is dead weight. Counting the teeth and dividing is just an easy way to determine the approximate gear ratio, but you can very easily change the gear ratio slightly by changing the pinion depth -- which is why the difference between 4.11 and 4.10 is negligible after you factor in other fudge factors such as tire diameter due to wear, age (ring and pinion settings will change with use), tire pressure, weight distribution (which affects tire diameter), and so on. "Backlash" is then the margin of error between the teeth count and the effective diameters that the gears are using, allowing us to run a gear set that has been labeled 4.10 as really 4.097, 4.103, and so on.

NOT TRUE! It's all about tooth count. Thats why there are so many different gear ratios out there. And, even if you didn't have teeth to count then to change ratios the toothless input shaft and the outer ring gears size would have to be changed. An 8.8 is aprox. 8.8 inch ring gear. With that set in stone, the only way to change ratio is through tooth counts. Pinion and ring gear. Generaly the lower the gear ratio the less teeth on the pinion and more on ring.
 






97AWDX,
I'm not an off road guy so I had never even considered Yukon gears, thanks for the correction.

As for backlash, sure you can shim the carrier one way or another but any change you get in the number of times the driveshaft rotates versus the axle is due to "slop". There is no good reason to set the backlash outside of the acceptable range and there is certainly no performance advantage to it.
 






So i dont have to change out my rear end there is other options i was thinking that the easyst way was to get a ranger back end and then hook it up with a diff rent supention set up in the rear but thats a lot of work
 






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