[wojtizzlator]

bmyohn those gears tht are next to your ring gear i believe is the limited slip well im pretty damn sure it is

[marlow]

what is it in btw?

[bmyohn]

Originally Posted by wojtizzlator

bmyohn those gears tht are next to your ring gear i believe is the limited slip well im pretty damn sure it is

i think thats the limited slip part as well. i dont feel as embarassed when i go to do a burnout now. the one mark was pretty sad...lol


btw, those pics are from a 8.8" out of a 97 explorer.

[marlow]

i thought it looked a lot like an 8.8

[MBJR9]

Originally Posted by bmyohn

i think thats the limited slip part as well.

Yep it is. The thing (not sure of the technical term, it's shaped like an S sorta) acts like a spring and keeps the wheels locked together when going straight and while cornering the side force compresses the spring allowing the spider gears to turn freely which allows the rear to function as an open (peg leg) unit while cornering.

[Timo_90xj]

Originally Posted by marlow

my mustang lays two very nice 315 sized lsd burnout marks and if you raise the back end and spin one wheel, the other often spins in the opposite direction. just and example of when the wheel spin method doesnt work

Thanks Finally someone else bumped in with this comment, so it's not just me who thinks spinning the wheels in the air is not a good method.

Personally, I usually check either by doing slow, tight turns on dry pavement - or usually just flooring it and checking how many skid marks I find behind the car ..and if I don't find any, I won't buy it due to lack of bhp/torque

[tntempest]

I have owned a bunch of lsd mustangs, and if your wheel is turning the opposite way , then your clutches are gone, and it may work in a straight line, but not if you floor it in a corner.

My jeep has put down two streaks before, but I do not have an LSD. But usually it puts down one as can be proven by my bald right rear tire.

Every LSD I have ever seen will turn the wheel in the same direction if it is in good operating condition and has friction modifier if needed. That is the whole point to turn, if the other wheel loses traction. So if you spin the other way your clutch packs are gone, because the clutches are not holding.

However if your brakes are dragging it could cause it not to turn or maybe turn a little in the opposite direction.

[marlow]

Originally Posted by MBJR9

Yep it is. The thing (not sure of the technical term, it's shaped like an S sorta) acts like a spring and keeps the wheels locked together when going straight and while cornering the side force compresses the spring allowing the spider gears to turn freely which allows the rear to function as an open (peg leg) unit while cornering.

not really a technical term - its just called an s-spring

[19OlllllllO41]

Originally Posted by mtl4life

Thanks for all the replies everyone. Now that it's verified that my diff is open, I have one other question. The fluid I used has friction modifiers in it. Will this cause any issues with an open differential?

No not at all, you will be just fine. Most gear oils today (i.e. valvoline, mobil 1, etc) all have the friction modifiers in them, but are not only for LSD rear ends.

[MBJR9]

Originally Posted by marlow

not really a technical term - its just called an s-spring

Well that makes sense !

[Timo_90xj]

Originally Posted by tntempest

I have owned a bunch of lsd mustangs, and if your wheel is turning the opposite way , then your clutches are gone, and it may work in a straight line, but not if you floor it in a corner.

My jeep has put down two streaks before, but I do not have an LSD. But usually it puts down one as can be proven by my bald right rear tire.

Every LSD I have ever seen will turn the wheel in the same direction if it is in good operating condition and has friction modifier if needed. That is the whole point to turn, if the other wheel loses traction. So if you spin the other way your clutch packs are gone, because the clutches are not holding.

However if your brakes are dragging it could cause it not to turn or maybe turn a little in the opposite direction.

If you didn't know, clutch-based LSD units can be built in many different ways, to provide the handling and/ or safety charasteristics the manufacturer wants. You can modify the "locking" amount, you can modifa torque bias, you can modify how the clutches engage/ disengage, etc.. It's all in the way how the differential is designed.

You also have to remember that clutch-type limited slips respond to driveshaft torque. I do know that clutch-type LSDs always have both axle shafts at least slightly coupled, but it is possible to build a LSD so that in a "no torque" situation it behaves very much like an open diff. That means, with no torque applied through DS, both wheels won't turn in thh same direction if they are up in the air (or even if the other tire is on the ground and the other up in teh air, tranny in neutral). Then, when torque is applied through the DS, the clutch packs are pressed tighter together and splitting the torque to both wheels.

I don't know what are the static spring loads for teh clutch packs on the F8.8, the D35 or the two different LSD units I had in my Opel Omegas. I do know however that the clutch packs in the F8.8 have considerably more static preload on the packs than on my Opel rear-ends (both had independent rear suspension). More static preload automatically results in both wheels turning the same direction even under no load (ie. both wheels in the air and turning the other wheel). It doesn't, however, tell how tightly the packs are pressed together under load.

IIRC, both F8.8 and D35 trac-lok LSDs are ~25% locking. The ones on my Opel where ~50% locking, and you can definitely feel the difference between those while driving. Neither of the Opel diffs turned the wheels in same direction if I tried the method - not once. My Ford 8.8 did it every time I tried (I never had it mounted under my XJ with the LSD), the D35 did it sometimes but not every time.

[tntempest]

I still stand by what I say, however I should have said my experience is with Clutch type, from WIKI. So according to this, the wheels should turn together if off the ground. Torsen, torque sensing, viscous and others may be different

The clutch type LSD responds to driveshaft torque. The more driveshaft input torque present, the harder the clutches are pressed together, and thus the more closely the drive wheels are coupled to each other.

With no / little input torque (trailing throttle / gearbox in neutral / main clutch depressed) the drive wheels are still coupled somewhat as the clutches are always in contact to some degree, producing friction. The amount of preload (hence static coupling) on the clutches is determined by the general condition (wear) of the clutches and by how tightly they are shimmed.

So the moral of the story is if you have a clutch type and the wheels don't turn the same way, then you have a very worn or low locking LSD.

[manofmany]

Originally Posted by bmyohn

here is my limited slip out of my 8.8"

Looks like mine.

Is there an advantage to having an LSD?

[Timo_90xj]

Originally Posted by tntempest

.... ....
... ...

So the moral of the story is if you have a clutch type and the wheels don't turn the same way, then you have a very worn or low locking LSD.

IMO, the moral of the story is that if the wheels aren't turning the same way, you either have an open diff, worn clutch packs on your LSD


OR


you have a very low-locking limited slip when there is no torque applied through DS ..in other words, this kind of LSD would have very low static (pre)load on the clutch packs. But having very low static (pre)load on the clutch packs doesn't necessarily mean the limited slip diff is of low- locking type when torque is applied.

Like I said, never did the tires spin the same direction on my Opel Omegas, but the limited slip diffs worked absolutely FLAWLESSLY on every possible situation where I put them. Dry asphalt, wet asphalt, sand, mud, snow, ice, other tire on ice other on asphalt, driving straight, cornering.. every possible situation. Like I already wrote, they both were 50% locking.


I'm not saying all LSDs behave like that - my F8.8 was EXACTLY like you wrote. My D35 was like that sometimes (don't ask me why?). My Opel rear-ends were never like that, one of my friends has a limited slip on his (E30- body) BMW 320i, it acts just like my Opel diffs. Two other friends had limited slips on their Chrysler LeBarons (early 80s models), both wheels turned the same direction.

It all depends on the design, so I guess one could say we both are correct, and we both are wrong, depending on how you look at it

[bmyohn]

Originally Posted by manofmany

Looks like mine.

Is there an advantage to having an LSD?

it means that when you hit the gas, power will stay with both the wheels. in an open differential, the power will go to the wheel that has lost traction. therefore, if you get in an offroad situation where one tire gets off the ground, u will be in trouble since all the power is going to the tire with no traction. rather then the power going to the tire that still on the ground like you would want, it goes to the tire thats in the air.

-Brendan