03 expy diff questions - limited slip?
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Mountain Pass
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03 expy diff questions - limited slip?
Was a limited slip diff an option on the 03 expys? If not are they all limited slip or not? Were different gearing ratios a factory option?
What does a limited slip diff do for you exactly? From what I understand it makes both rear wheels turn at the same rate instead of only one just pushing but I don't understand the relationship with the diff and tranny and how all that works so if someone wants to explain that would be great.
What does a limited slip diff do for you exactly? From what I understand it makes both rear wheels turn at the same rate instead of only one just pushing but I don't understand the relationship with the diff and tranny and how all that works so if someone wants to explain that would be great.
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Short version
All things being equal ... weight on each tire, the amount of available traction to both wheels (rear) and overall diameter and width and compound of each tire. You would not need the help of a limited slip diff. Both tires could wiz you up the highway with grace, which is what happens most of the time any way. Throw in rain, mud, snow or that ditch you were trying to cross and every thing gets out of balance. The limited slip diff is just a method of tying both axles together in a low traction situation in order to help the vehicle move forward or back until traction becomes equal for both tires again. It stops the axle with the least amount of traction from spinning freely and forces some of the torque to be shifted to the other axle. But it must be able to slip in order for the vehicle make turns. The ultimate limited slip device would be a spool. But spools lock both axles together all the time. While the transmission take power from the engine to the diff while allowing the engine to stay with-in its power and torque band. 
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Mountain Pass
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From: IL
thanks for the clarification on what limited slip is.
Now does the expy have it? Front or rear or both?
Did the late models (03+) come with different size gearing available as a factory option?
Now does the expy have it? Front or rear or both?
Did the late models (03+) come with different size gearing available as a factory option?
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Limited slip differentials are optional on the rear and not available on the front due to steering.
I think the '03 and '04's have optional gearing (all '97 to '02's do), although I think I saw somewhere that all future models get a 3.73 rear end.
I think the '03 and '04's have optional gearing (all '97 to '02's do), although I think I saw somewhere that all future models get a 3.73 rear end.
Logistics Pro
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Look inside the jamb of the driver's door. Look for an axle code. Here are the codes for prior year models (don't know if they still apply or not).
Expy Gear Ratios:
19—3.55 NLS
17—3.31 NLS
H9—3.55 LS
H7—3.31 LS
H6—3.73 LS
Expy Gear Ratios:
19—3.55 NLS
17—3.31 NLS
H9—3.55 LS
H7—3.31 LS
H6—3.73 LS
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5th Wheeling
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I thought all 2003 had LS, mine does not but had AdvanceTrac which does not need or permit a LS diff. Yes they've had a lot of issues with early production LS diffs. No suprise as it is ?the? first common truck-grade independent rear suspension (Hummer and Unimogs dont count!).
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Mountain Pass
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From: IL
I took a quick look yesterday when getting out for work and I did see an H6 on the door label. I am not sure if that could be referring to something else though. Where on the label should I be looking exactly and is there a heading for the part I should be looking at?
I looked on fords web site and I didn't see any options on the current expys for different gear ratios or limited slip. This is curious as I would have liked to know that before buying mine. If it is indead H6 meaning it is limited slip and 3.73 gears then that would have been my decision at point of purchase anyway so that is good. I wonder if they put 3.73 and limited slip on all 4x4 models. Anyone know?
I looked on fords web site and I didn't see any options on the current expys for different gear ratios or limited slip. This is curious as I would have liked to know that before buying mine. If it is indead H6 meaning it is limited slip and 3.73 gears then that would have been my decision at point of purchase anyway so that is good. I wonder if they put 3.73 and limited slip on all 4x4 models. Anyone know?
Last edited by dirtriderdan; Jul 3, 2004 at 10:49 PM.