Differential question

00ls5spd

00ls5spd

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O.k. guys....I don't know anything about differentials.
All I know is that my Manual LS has the 3.31 rear end with a final gear ratio of 1:1 I know the automatic LS's had a different rear end. Anyways to my question. My differential needs work, would it benefit me in any way to change my gearing?
 
Maybe. But simply changing gears isn't as simple as it sounds. I would call around a few junkyards in your area and see if you can find a 3:58 ratio rear end from a same year Thunderbird. A yard shouldn't want more than 2 or 300 bucks for the setup and you can swap the thing in yourself in about a day if you work consistently. That will give you some extra power to the wheels, but it will also raise your RPM on the highway. Going backwards to the lower ratio wont help you at all, unless you want less power to the wheels and only slightly better fuel mileage.

Out of curiosity, what kind of work needs to be done on your diff now?
 
It changes the amount of torque which is transfered to the ground, but the amount of power the engine puts out stays the same.
You can dyno a car with 3:11s vs a car with 4:10s and see a difference in the power output at the wheels, even though they both might have the same engine.
 
00ls5spd said:
O.k. guys....I don't know anything about differentials.
All I know is that my Manual LS has the 3.31 rear end with a final gear ratio of 1:1 I know the automatic LS's had a different rear end. Anyways to my question. My differential needs work, would it benefit me in any way to change my gearing?
Click to expand...

Your 5th gear isn't 1-1, likely 4th is...5th is overdrive and probably around .65-.75 ratio. 00-02 autos had the 3.31s also. Only early 00 had the 3.58s and some manuals had 3.07s not sure the rule there. All 03-06 had the 3.58s but from what I've read not seen with my own 2 hands you can't interchange from Gen1 to Gen2. Axle length is different or something to that effect.

Gearing up will put your power to the wheels better and increase acceleration, gearing down will give lower cruizing rpms. Gas mileage would be affected only slightly with the minor changes we are talking here.
 
Out of curiosity, what kind of work needs to be done on your diff now?[/QUOTE]

I haven't had anything done yet, but I believe I have the ring gear issue with the differential hum at about 40-70mph. I don't think its a wheel bearing because I only hear the hum under acceleration. anyways any info you guys have will help.
 
Justin, all V6 autos have 3.58, you should fing one from 00-02 V6 and swap it. I was thinking of doing it till I saw that mine is already 3.58 (01 V6 auto sport).
 
HyeLifeLS said:
Justin, all V6 autos have 3.58, you should fing one from 00-02 V6 and swap it. I was thinking of doing it till I saw that mine is already 3.58 (01 V6 auto sport).
Click to expand...

Not necessarily HyeLife, only VERY early 00's had the 3.58's. I owned a later 00 V6 and a 02 V8 and they both has 3.31's. I did this 3.58 swap in my 02 4 years ago so I remember how crazy it was to find these parts.

You can get a early 00 with 3.58's or a 02 T-Bird and they will match up.

The only other thing I heard about the V6 is they may have skinnier axles, those may have to swapped with it as well.
 
97stscaddy said:
It changes the amount of torque which is transfered to the ground
Click to expand...



Re-gearing does not change the AMOUNT of torque put to the ground. What re-gearing does is just allow that amount of torque to come on earlier in the vehicle acceleration. This is a big benefit to an LS where even the V8 is a total dog off the line as it will allow the engine to get to its sweet spot sooner.
 
Maybe, but mine is a 01 V6 and it has 3.58. Interesting.

02V8Sport said:
Not necessarily HyeLife, only VERY early 00's had the 3.58's. I owned a later 00 V6 and a 02 V8 and they both has 3.31's. I did this 3.58 swap in my 02 4 years ago so I remember how crazy it was to find these parts.

You can get a early 00 with 3.58's or a 02 T-Bird and they will match up.

The only other thing I heard about the V6 is they may have skinnier axles, those may have to swapped with it as well.
Click to expand...
 
ILLS said:
Re-gearing does not change the AMOUNT of torque put to the ground. What re-gearing does is just allow that amount of torque to come on earlier in the vehicle acceleration. This is a big benefit to an LS where even the V8 is a total dog off the line as it will allow the engine to get to its sweet spot sooner.
Click to expand...

+1
 
I wish people would fact check before posting.

Yes top gear on the 5-speed manuals is 1:1, NOT overdrive (one of the features that BMW has unfortunately changed in its cars in the last decade).

The axle ratios for the manuals were 3.07 (very early cars had the 3.31 ratios)

So a swap to the V-6 auto would give a 3.58 ratio (IMHO not too useful for on-road operation). While 00 -03 v-8s had the 3.31 ratio its in a different case than the v-6 (iron rather than aluminum). Swapping a later manual would give you a 3.07.

If yours is a 3.31 rear I think thats the best one for the manual transmission cars.
 
pragmatic said:
So a swap to the V-6 auto would give a 3.58 ratio (IMHO not too useful for on-road operation).
Click to expand...



Um 3.58's (or your mathematical equiv) aren't even that numerically high of a gear. Where does your logic in saying they aren't useful for on-road operation come from? Heck I see people running 4.10's in allot of cars with similar 5th gear ratio's and are just fine with it. Did you get 4.58 and 3.58 mixed up or something? 3.58's aren't that big at all especially with a small V6 like the LS has or even the tiny/torqueless V8 that the LS has either.


I have also never seen a Ford 5 speed transmission that didn't have 4th as being the 1:1 and 5th as overdrive. Just like the fella that just posted above me; I would like to know where you got your information from? Looks like the M5 221 tranny has the 1:1 at 4th gear, not 5th gear.
 
ILLS said:
Um 3.58's (or your mathematical equiv) aren't even that numerically high of a gear. Where does your logic in saying they aren't useful for on-road operation come from? Heck I see people running 4.10's in allot of cars with similar 5th gear ratio's and are just fine with it. Did you get 4.58 and 3.58 mixed up or something? 3.58's aren't that big at all especially with a small V6 like the LS has or even the tiny/torqueless V8 that the LS has either.

I have also never seen a Ford 5 speed transmission that didn't have 4th as being the 1:1 and 5th as overdrive. Just like the fella that just posted above me; I would like to know where you got your information from? Looks like the M5 221 tranny has the 1:1 at 4th gear, not 5th gear.
Click to expand...

Most Getrags 5-speeds used by BMW in the late 80s and early 90s were non-overdrive in top (do a search for getrag 262CR). This lowers noise and wear in that the countershaft is not used on the highway. I still think a non-overdrive top with a suitable axle ratio is the way to go.

As for the LS I defer to the Ford Press releases for the car

http://media.ford.com/products/presskit_print.cfm?vehicle_id=65

Which states
Gear Ratios
V-6 Auto (1st - 5th) 3.25, 2.44, 1.55, 1.00, 0.75
V-6 Manual (1st - 5th) 4.23, 2.53, 1.66, 1.22, 1.00
V-8 Auto (1st - 5th) 3.25, 2.44, 1.55, 1.00, 0.75

Axles
V-6 Auto 3.58
V-6 Manual 3.07
V-8 Auto 3.31

Early manuals had the 3.31s (so I have heard).
After 2003 they all had 3.58 (but again I've been told they don't swap because the cases are different)

The non-overdrive top is why I said the 3.58 would be unsuitable for a street vehicle. While 4.11 were around in the 60s with non-overdrives trans they were not the best vehicles for highway use. A 3.58 with the non-overdrive top gear would be equivalent to using a 4.77 with the automatic transmission LS when cruising down the highway. As it is the 3.07s are the same as an automatic using 4.09s (3.07 divided by the 0.75 top gear on the automatics).

Again if you have the 3:31, I think you have the best ratio around for the 5-speed LS. I've been told a V-8 will not swap in easily because the case is different (iron rather than aluminum).

I have the 3.07 and just make use of 3rd gear for most two lane passing, which takes me from 4000 rpm (at 60) to 6700 (at 100).
 
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I didn't check the math on your figures, but the way you had it worded was that AFTER the swap that the final drive would be comparable to a 3.58. I didn't see where you mentioned anything about swapping a 3.58 itself in there.
 
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