i was wondering what is the diff between the axle ratio sizes?
how come the Lightning's have a 3.73 and the regular's have a 3.55

thanks in advance

 

my supercrew with 3.55 gears has a locker on its rearend...

 

what does that mean...?
if that is a good thing then... man that's great.
if that is a bad thing then... bro, sorry to hear that.


ps.
do all Limited Slip axles come with the locker?

 

well, what i meant was that my axle is limited slip...

 

Limited Slip means that the axle will lock the rear wheels together when one of them slips sending traction to both rear wheels. A "Locker" is a rear end that has both rear wheels locked together all the time. This is good for competition or off-roading but not so great for street use. It causes some handling problems and is very hard on the differential on the street.

Also I am not completely sure of this but I know in 1998 the only ratio available in limited slip was 3.55...I think in 99 they changed this to the 3.73 available in addition to the 3.55. I'm pretty sure the reason the L's come with the 3.73 would be the improvement in preformance and accerlation(sic).

 

the axle ratio is the number of revolutions of the ring gear to 1 revolution of the pinion. so with a 3.55 rear end, the drive shaft has to turn just over 3 1/2 times to turn the wheel once. the higher the number, the more leverage.

so a 3.08 rear would be like trying to loosen a bolt with a stubby wrench. a 3.55 would be like using a 1/2 inch drive ratchet, and a 3.73 rear would be like using a breaker bar.

as far as the difference between a limited slip and a locker...
you know how if you get a tire on a patch of ice... torque always travels the path of least resistance. thats why if you have one wheel on that ice it is going to spin, and the other wheel that has traction will just sit there. if you have a limited slip that spinning tire will cause the limited slip unit to transfer power to the other wheel. think of it like a child proof medicine jar. you can just turn it round and round (like and open Diff) but when you press down on it, it grabs (like a limited slip)

a locker joins the two axles together and does not allow any slip. with a locker you can have one wheel in the air, and it will not spin any more than the one on the ground, (so the power still goes to the ground)

of course this is a very basic description. it can be much more in depth with automatic vs. selectable lockers, and don't forget about spools.


hope this helps some.

 

thanks!
now i have an idea of what it means and a basic understaing of how it works.
really thanks.

regarding the 3.73 and 3.55 can i get a 3.73 on my truck?
and is there any higher raio's like 4.1 (i saw it in another post talking about it)?

 

look up Randy's ring and pinion, Precision Gear , or look in a 4x4 magazine. there are many places that make many different ratios. call a couple gear mfgs and they can help you figure out what ratio will suit your needs best.

 

I have a 3.55 in my 1987, however it is a non-limited slip, i would like to change that to a limited slip. Is a change like that difficult or expensive.

 

I have a 3.55 in my 1987, however it is a non-limited slip, i would like to change that to a limited slip. Is a change like that difficult or expensive.

 

FDPIK,
i guess the best thing to do is check with the above post that muddytrux made regarding 4x4 magazines and call around different mfs.
i am sure they would be able to tell you wheter or not it's possible and how much it costs....

btw muddytrux, thanks again.

 

your looking at about $300 to have a shop put a limited slip unit in. you can pick one up for under $200 if you shop around. then you'll have to find a shop to put it in. It's one of those things thats possible to do yourself, but if you have to ask you'd better let a pro do it. if it is not done just right you can blow up your rear end.

I'd suggest going to fourwheeler.com or fourwheelandoffroad.com and search their archives. I know both mags have done extensive articles on the differances, advantages, dissadvantages, and instalations of l.slips, lockers, and spools. it would be an advantage to know as much as possable about them before you shop. that way you don't end up with more (or less) than what you need.

just as a guide, if you are not running oversized tires a 3.55 LS is about perfect. if you want quicker acceleration, or plan on doing a lot of towing, then maybe a 3.73 LS. if its just a hiway cruser and you want better gas mileage, then maybe a 3.08 LS. then if you want a lot of off road and don't care as much about on road handleing, then look at lockers and higher ratios to offset the larger tires..

 

oh yeah one more thing, if it's for a 4x4, you'll of course have to buy gears for the front too if you change the gear ratio in the back. I'm sure you knew that, but just to make sure.

 

Ok, great thanks, now i know how to get started. I have a 1997 XLT 4X2. I plan on someday towing a pop-up camper. It is a 4.2 V6 with a 5sp manual tranny.

I am running oversize tires, i bought the truck used about 2 weeks ago, they had just put new tires on (265/75 R16) , the door pannel called for 235/70 R16. I like the bigger tires and it feels like the truck is handling it well.

Thanks again for the response.

 

I run the same setup.265-75-r16 tires, with 3.55 gears, a 4.2 and a 5-speed. you'll have no trouble what so ever towing a little pop up camper. mine is a 19 foot pop up, and I have to keep looking back to make sure it's still there. you won't even notice it. I've also pulled a 22 foot tandem axle trailer with my Bronco II on top. thats a struggle up some hills, and if i did that very offten, then i might swap in 3.73 gears. i drive an average of about 80 miles per day, so going to bigger gears would hurt me too much on gas to be worth it just for occasional towing.