S4 differentials are rebuildable, so when you waste it you can fix it. Can't do that with a Torsen or a viscous differential.

As far as figuring out the ring and pinion:

Put a chalk mark on the wheel facing down. Make a matching mark on the ground at the same spot.

Put a chalk mark on the drive shaft coming from the transmission facing straight down.

Turn the drive shaft exactly 4 times.

Is the mark on the tire past or before the mark on the ground. If the wheel only turned 3.9 times when the drive shaft turned 4 times, you have a 3.9 ring and Pinion.

If it turned more than 4 times (such as 4 times plus an inch) you have a 4.1 rear end.

 

sweet, I really didnt want to take it apart.

I'll do that tomorrow took the day off to sand and primer...

 

Yes a torsen can't be rebuilt, but at the same time they don't wear like a clutch type and there's no special un-replaceable fluid that breaks down like a viscous type. No it probably won't live forever, but properly taken care of it should easily last the life of the car.

 

Hail the all mighty icemark. how ever, i dont think this test would work with a viscous differntial due to that if its not spun fast enough it will not move the fluid fast enough to move the "paddle"(for lack of a better term) conection on the other side of the axle.

 

So much for having known all the owners. Somewhere in that chain someone swapped in an S4 diff. Seems that girl may have been messin around with you!

-b

 

it usually takes a couple revolutions with the viscous... usually you don't get any spin from the opposite wheel until the fluid starts to solidify but I really didn't want to confuse him since he seemed already to be in a little over his head in tech talk.

 

I have been working on cars half my life.

all the shops I have worked in, stayed away from Wankel, so I really never got a chance to work on them.

I fine them fun to drive. and a very smart design.

so the viscous type it is like the hydrodynamic friction, and The clutch type LSD responds to driveshaft torque.

wrankin you said it.

like to know more about my 7

 

Thank you all for all the help whit this damn rear end

Icemark said it. there is no lsd's in 91. and theres still not one.. lol

and I knew I had a lsd, just got lied to, by the old owner.. starting to wounder if her son got the intake ported....

does it matter what year s4 diff when I go get clutches one day?


once more thank you

 

Most shops stay away from them because there too "specilized" from a business prespective.

i dont think hydromaticfirction and viscous is quite the same, its just like really thick fluild with a "paddle" like device on the end the "loose" axleshaft" when the fluid turns fast, becasue its so thick, it spins the other paddle and in turn the axle shaft.

you can rebuild a tortion differntial, its just like any other moving part. seals and berings.

tortion is a multiplication differnental, its mechanicaly conected, but the side that is not spinning recives x times the torque that the spining wheel is via internal differnental gear ratios, the common one on ebay is like 4 or 3 to 1. So for example: you have a 3:1 tortion ratio differnential, your car puts down 120lbft at the wheels, your drive wheel starts spining, the torque going to the drive wheel is then mulitplyed by 3 and sent to the wheel that is not spining, thus giving you 360lbft to the recesive wheel, but also reduces the speed of the recesive (360lbft) wheel by a factor of 1/3rd.

In actuality this happens so fast that its not like one wheel spins and then the other blows a huge white cloud of white smoke due to the torque. It acts more like a less "kicking" engagemnt like a clutch type.

 

Sorry I didn't mean to offend you, but when you started the thread calling a LSD a posi or positive, that showed a lack of education on cars... regardless of what type of engine.

Calling a LSD a Posi, is like calling all refrigerators Kenmores or all car radios Alpines. Posi-drive or Posi rear ends are a trademark for GM/Buick... and not an accurate description for a LSD.

The most common LSDs are:

The clutch type LSD does 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.

The viscous type is generally simpler, it relies on hydrodynamic friction from fluids with high viscosity. Silicone-based oils are often used. Here, a cylindrical chamber of fluid filled with a stack of perforated discs rotates with the normal motion of the output shafts. The inside surface of the chamber is coupled to one of the driveshafts, and the outside coupled to the differential carrier. Half of the discs are connected to the inner, the other half to the outer, alternating inner/outer in the stack. Differential motion forces the interleaved discs to move through the fluid against each other. In some viscous couplings when speed is maintained the fluid will accumulate heat due to friction. This heat will cause the fluid to expand, and expand the coupler causing the discs to be pulled together resulting in a non-viscous plate to plate friction and a dramatic drop in speed difference. This is known as the hump phenomenon and it allows the side of the coupler to gently lock. In contrast to the mechanical type, the limiting action is much softer and more proportional to the slip, and so is easier to cope with for the average driver.

Viscous LSDs are less efficient than mechanical types, that is, they "lose" some power. They do not stand up well to abuse. In particular, any sustained load which overheats the silicone results in sudden permanent loss of the differential effect. They do have the virtue of failing gracefully, reverting to semi-open differential behavior. Typically a visco-differential that has covered 60,000 miles or more will be functioning largely as an open differential; this is a known weakness of the original Miata. The silicone oil is factory sealed in a separate chamber from the gear oil surrounding the rest of the differential. This is not serviceable and when the differential's behavior deteriorates, the VLSD center is replaced.

Geared, torque-sensitive mechanical limited slip differentials utilize worm gears to "sense" torque on one shaft. The most famous versions are:

* Torsen differential invented by Vernon Gleasman in 1958, then sold to Gleason Corporation, who started marketing it in 1982 (the Mazda and Toyota units called Torque sensing conical Limited Slip Differentials are based off of this design).
* Quaife differential, sold under the name Automatic Torque Biasing Differential (ATB), covered by European Patent No. 130806A2.
* Eaton Corporation differential, sold under the name Eaton Detroit Truetrac.

Geared LSDs are less prone to wear than the clutch type, but both output shafts have to be loaded to keep the proper torque distribution characteristics. Once an output shaft becomes free (e.g., one driven wheel lifts off the ground; or a summer tire comes over ice while another is on dry tarmac when the car goes uphill), no torque is transmitted to the second shaft and the torque-sensitive differential behaves like an open differential.

Geared LSDs are dependent on the torque and not on the speed difference between the output shafts. Such differentials may not be adequate on extremely slippery surfaces such as ice (or thin air, when a drive wheel loses ground contact altogether).

Geared LSDs typically are used:

* to reduce torque steer in front-wheel drive vehicles;
* as a center differential in four-wheel drive (e.g., on the Audi Quattro);
* in rear-wheel drive vehicles, to maximize traction and make oversteer easier to manage (as in drifting). Although, for extreme drifting, a geared LSD is less effective compared to a clutch type LSD.

 

well I did grow up a chevy man,
and I'm not offended, there is always someone smarter then you out there, its picking there head that makes you smarter..