Well, as many of you know, we have had a local customer's car for about a month while we performed a laundry list of mods to the car as far as additions. One of the mods this customer elected as an OS Giken locking LSD like this:



The car also had a Energy Motor Mounts installed at the same time. The car was a tremendous difference after both mods where added to here. She was much more stable overall. No torque steer, very predictable and responsive as a whole.

The car was able to be slammed into corners at 12 PSI with 100% throttle and she was pulling into the turn VERY hard. The LSD was absolutely the best mod for this car he could have done. She has the ability to dart in and out of corners with ease. Steering responsiveness is sooo there especially with his 245/40 Dunlop Direzzas on Dan G RPF1s, KW V2 coilovers, Energy mounts and this LSD. The car's traction is now a function of tire grip and suspension tuning and nothing else.

Hands down, the BEST turbo tC I have driven with a Diff. I have driven quite a few Quaife cars, and none compare to the feel of this car.

On a side note, Don is even harder to please than me, and even he was "wowed" about this diff as a whole.

Figured I would share.

This diff is in stock and for sale here at Dezod....
http://www.dezod.com/pd-os-giken-lim...tial-2azfe.cfm

 

doenst this style of diff require more maintnence and if so can you break down roughly what is required and a price?

 

do you still need to buy the parts kit just like with the TRD LSD?

 

Depends on how it's driven. For example, a race car will require more frequent maintenance than a street car.

This is a friction disc based full locking diff. These tend to create more heat in the trans case than a torque biasing diff like Quaife/TRD. As a result of the added heat, a heavier duty fluid will need to be run, but the selection of the proper diff fluid is essential because the diff is in the same housing as the trans, syncros and gears. This not like a RWD Supra or IS300 where they are separated.

The proper fluid to run, after some trial and error, is very specific. A race app might want to use a shock-proof heavy or mixture where the fluid is something like 75w140. These diffs require a thick fluid because of the heat, however your car only calls for 75w90 GL4/GL5.

GL5 has a friction modifier, which is near essential for this diff. You do not want the friction plates to bind at low speeds, they are supposed to slide across one another in this scenario, but at the onset of TQ, fully lock in a 1.1 ratio.

So other than requirements of fluid, service interval will be contingent upon how you drive the car. A normal driven street car, 3K miles for first fluid flush to ensure that all contaminants are flushed from the system. Then an interval of 30K miles will do for flush and refill of fluid.

Lastly, we tried Redline MT90 with no success on this diff. We are now running Motul Gear 300 and she runs perfect.

 

Yes sir.

 

On a side note, Don said you he recommends the ring gear bolts, race bearing set and speed-o gear for ease of install.

 

so the clutch packs within the diff wouldnt have to be replaced prior to 30K? i was under the impression that they wore out eventually.

 

They do wear out eventually, and if you are making say 400+whp and beating the ever loving snot out of it every second, they will go faster. OS claims to have some cars in Japan that have over 70K miles on them without being rebuilt. So you be the judge!

 

Well thats good news. thanks for the infoz paul. You definatley put this diff back on the table for me.

 

I've had my eye on the OS, but finding a shop that i think would touch it is hard. Might have to talk to you about it paul when that time comes.......wow, seems so far away, ahh!

 

Good to hear this review! Sounds like its definitely worth it over the TRD then.

 

redline didint work huh? ive found redline to be the best fluid in my tranny so far only fluid that gives me perfect shiffting during my racing.. id hate to have to change it becasue of diff Can the trd lsd be used with mt90?

 

PTuning uses Mt90 on their TA tC with the TRD LSD...

 

This style of diff requires the same maintenance any transmission requires. Change the fluid at the specific interval and call it a day. Rebuilding is not maintenance and I do not expect to see any scion owner to ever have to really rebuild one.

I would recommend it if you are doing this yourself. I don't recommend doing this yourself if you do not have experience doing this kind of work or access to the special tools or semi-proper tools to remove the specific parts listed in the service manual.

Ring bolts are not required unless they come out stripped or cross threaded and you can see this on diffs with a lot of miles. It is nice to have them handy so that you don't have to stop what you are doing to order parts and wait a few days because they WILL NOT be in stock at the dealer etc. However they are not required. Differential carrier bearings and races are optional if you destroy the bearings while removing them. If the transmission has relatively low miles you can get away with swapping the bearings. This way you do not have to set new preloads with shims etc. You also do not have to remove the races from the case which is a PITA for the average DIYer. I do highly recommend getting a new speedo gear. Makes life much easier, especially if you don't have a way of removing the bearings in the first place. (if you don't you shouldn't be doing this job)

They are friction material so in essence eventually they will wear out. You will probably never see that happen in a street driven car that has had the fluid changed on a regular basis. This diff can support more horsepower than the average TC owner may ever make.

If anyone decides they would like a diff installed they can always contact us and we can arrange to have you ship your transmission here to me and I can install the differential for you and ship it back.

Redline MT-90 is a great fluid and was my first choice. MT-90 is specifically a GL-4 fluid. This fluid does not have a friction modifier in it. The TRD/Quaife diff can run fine on MT-90 becuase it does not have any friction plates in it and there fore does not require the additive that makes fluids a GL-5 rating. MT-90 shears off too easily and does not evenly coat the friction material in the diff. You need a friction modified fluid to allow the plates to slip and lide against each other. If you do not use this then you will create a binding condition known as crow hopping.

The good thing is that it is easier to find a fluid with GL-5 then it is to find a fluid with GL-4 only. Most all gear fluilds commerically sold meet the GL-5 rating. The E350 transmission calls for a 75w90 GL4 or GL5 rated fluid. So it makes no difference which you run for the stock setup. This diff requires a GL5 fluid. So just make sure you run GL5. If you are looking for a synthetic transmission fluid that meets all these requirements then check out Motul Gear 300. However anything will work. Motul is just a higher tier fluid which stands up to much more abuse.

http://www.dezod.com/pd-motul-1l-bot...uid-105-qt.cfm

I have driven both Quaife/TRD and OS giken diff cars. The OS giken is a little louder but it has much more in terms of mechanical moving parts. It is a true locking diff. Much like the old Detroit lockers of old days but these are the best type performing differentials available, period.

These lock no matter what because they are preloaded by springs and clutch plates. There is no choice. As soon as the power is applied the wheels are locked. The quaife/trd can become unsettled in a launch or heavy turn if the wheel lifts from three wheeling or wheel hop.

 

Very Interested in this LSD and plan on start saving for it after I get my turbo kit. For an extra $300 over other LSD isn't that bad. I've been hearing nothing but great things about OS and is worth every penny.

 

You will not be disappointed in this diff. It's