This site contains car modification and auto upgrade information specifically for the turbo import Toyota JZX90 MarkII TourerV, however the principles applied here can be mostly utilised regardless of the make or model of motor vehicle.
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Cusco LSD upgrade 16/3/2004
Open wheeler diffs are great if you are into leaving single black marks at every turn, but I was more interested in better cornering control and decent drive out of corners.
So Cusco came to the rescue with the Type RS 2 way mechanical limited slip diff you see here. The diff came wrapped in a plastic bag that was very oily. Obviously when they assemble and package the diff centres Cusco applies a liberal amount of oil everywhere. Makes sense really as the plates would otherwise be completely dry when the centre is first installed into the diff housing, even after the oil is put in. The resulting high friction would probably cause very high initial wear to the plates.
So after unwrapping the excessively oily bag, the mysterious mechanism is unveiled. This particular version of the LSD uses a spring mechanism for initial whereas the MZ version uses a cone type arrangement. Cusco make a very sturdy unit, and this one has 10 clutch pates on either side that are actuated by a pair of symmetrical cams that provide equal clamping force in both acceleration and deceleration. I am initially impressed by the apparent quality of this unit and it promises to be a very worthwhile mod.
This is the differential just after removal from the rear of the car. It doesn't look extremely large or bulky but it is surprisingly heavy. It weighs in at a very obese 40kg and is not the easiest item to extract from underneath the car.
The first step to removing the diff was to locate all of the bolts holding in the primary tailshaft and the two secondary driveshafts.
From this picture you can see where the mounting points are for the tailshaft, the two driveshafts and the three rear mounting points to the diff housing. As an aside, the whole rear suspension bolts to the cradle you see here and if you wanted to you could drop the whole rear end, suspension, brakes and all, by only removing a few, but substantially strong bolts.
There are a further two bolts at the front that mount the diff housing to the chassis
These mounting points can be seen from this photo. The diff mounts to the chassis with a pair of rubber bushes that provide some vibration absorption and help to reduce NVH levels. (Noise Vibration Harshness).
As you can see from this shot it seems that the stock exhaust is getting in the way, but in fact it helped the process by holding up the tailshaft and driveshafts up for me. The exhaust has a branching on the left of the picture that goes nowhere. One can only assume that it is a form of resonater chamber to help keep the exhaust volume at such a low level.
The rear sway bar can be seen in this shot. This proved to be a real pain in the ass as it was directly in the place where I needed to fit the ratchet, however I resolved this by using the jack at an appropriate point on the suspension which caused it to flex itself out of the way. I could have removed the sway bar I suppose but that would have involved more work and I am definitely infavour of reducing the necessary labour required to do the job. The bolts for the cradle mount were of a particularly large hex key. I needed to purchase a hex key of the appripriate size that I could use on my breaker bar. This method was extremely effective.
So once the bolts are all loose I rasied the jack up to take the weight and then removed all of the bolts and then lowered the jack. Wheel that fella out from under the car and the diff is sucessfully extracted from the car. Alternatively I caould have liad on my back and dropped the diff on my chest and broken a few ribs but I decided that this experience would not add much to the enjoyment of the day.
Next step was to remove the housing cover to see just what this thing looked like inside. As suspected, a cheap nasty open wheeler not deserving enough to be fitted to such a fine vehicle as the TourerV. Appropriately strong enough but not refined enough in its design to of any use performance wise.
OK so now I removed the four bolts holding the bearing caps on. It is then a matter of gently hammering the two drive flanges to remove them. This then allows the diff centre to be extracted from the housing.
Here we have the extracted diff centre and the drive flanges which have a short shaft attached. Also in this shot are the bearing caps and some other doodad that came off the taper roller bearings. Notice the pigskin mallet to the right of the shot. This is what I used to knock out the mini driveshaft thingies. Sorry if I am getting too technical, its tough finding the right names for things sometimes.
Here is another shot where you can also see the taper roller bearings a little more clearly.
Looking inside the housing, the pinion gear can be seen. What appears to be rust is actually a orangy-red grease that was probably applied at the factory when the diff was originally assembled.
Since the Cusco centre does not come with any gears, it is necessary to remove the crown wheel from the stock diff centre, and bolt it to the new cusco LSD centre. In order to do this it I placed the diff centre in a large vise to stop it moving around, and using a socket and breaker bar(oh what a wonderfully ubiquitous device it is) I managed (with some cursing and grunting) to unbolt the crown gear from the stock centre. I also separated the diff centre just to inspect it out of curiosity. It is also necessary to remove the bearings as these need to be reused as well. These are not easy to remove and require a fair amount of forcefulness to encourage them to relinquish their grip on the old diff centre which they have become very fond of. Eventually they relent, although I did partially damage one of the bearing cages.
So back to the lovely new LSD centre. Looking at the top of the unit, the top friction plate can be seen with its spiral grooves. The holes are probably fro heat dissipation as well as provide a free path for oil lubrication. Looking inside the centre of the unit, a spiral groove is obvious which undoubtedly help with oil transfer through the shafts to the bearings.
Flipping the diff centre over we can see where the bolts secure to hold the crown wheel in position. This is quite straight forward as it is a matter of bolting the crown wheel straight back on the same way it came off. It is important to torque these bolts on all at the same recommended torque setting whcih I can't recall at the moment.
Here the crown wheel is on the centre and bolted in. You can see the tabs on the underside of the diff centre. These are bent over the bolts to ensure they don't go anywhere. A correct torque setting would ensure that they never come loose, however the tabs are there as a precaution anyhow.
Perhaps I took too many photos at this point but here they are anyway just to provide a few more angles.
This shot shows the centre with the old bearings in place on the new diff centre. If you were pedantic you might also replace these bearings, depending on the mileage of the car and how brutal you were in their extraction. They should be pressed on but I smacked them on with my trusty pigskin mallet.
Damn, so many photos and not enough words to say. Here is another shot of ... you guessed it: THE DIFF.
Alright now, so the diff centre is all assembled, we have checked eveything is tightened, and it is time to place it back into the diff housing. I first made sure that the diff housing was spotless before I re-inserted the centre. A thourough wipe over with a clean rage removed any excess oil and residue that had buillt up over the years. It is quite certain that the oil in the diff was original from the factory and although it had only travelled some 50-60 thou kays, it was more than 10 years old and was beginning to get a little gummy.
The diff centre is gently inserted into the housing making sure the pinion meshes neatly. The bearing caps are bolted into place and the shafts are then belted back on. (somewhat carefully of course)
On last admiration of the LSD as we probably wont see it for a very long while if ever again (hopefully). The bolts are then toqued up and we are ready to put the cover back on. Before this is done, a layer of copper gasket stuff is applied liberally all over the mating surfaces. I gave the surface a good clean first by scraping the excess old gasket off with a knife. Once the new gasket is evenly spread, the cover plate is bolted on and the diff is filled with a good quality LSD oil.
When choosing an LSD oil ensure that the oil is appropriate for MECHANICAL LSD's as there are some diff oils that are not appropriate and can degrade the performance of you new diff.
Ok, so the diff is then reinstalled into the vehicle in the reverse order and then the car is taken for a few km's of light throttle driving to bed the new diff in.
The result is nothing short of amazing. The drive out of corners is phenomenal compared to the open wheeler, and although it is a bit clattery and screechy when performing low speed tight manouvres, the advantage of the improved traction, along with the massive improvement in control during a drift, is worth every bit of compromise that a diff such as this entails.
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RECENT MODS CHRONOLOGY
5-Jan-2007
Turbo pages and Headlights
I have recently added a new page about my single turbo conversion. There is a second page yet to come, but page one outlines some of the supporting components needed as well as the turbo itself.
Page 2 will be forthcoming where I detail the fitment of the turbo, manifold and wastegate.
I have also added a page for modifications to my headlights that should be very useful for owners of import vehicles.
25-Jan-2007
Site Revamp
Wow, it has been a very long time since I worked on the site, but now I
am in the process of redesigning it so stay tuned as I add some more content
and attempt to bring this project up to date.
18-Mar-2006
Car Changes
Lots has happened since my last update on upgrades to the car. For instance
the car is now running a 2JZ bottom end and the gearbox has been completely
rebuilt with a stage 1.5 shift kit, beefier clutches and a 2800 rpm stall convertor.
To say that this has transformed the car is an understatement. The car is now
torque heaven, and is an absolute pleasure to drive. The lag that was sadly
felt with the 2.5L motor is now completely gone with the 3L and the stally.
When I can find time to update the site with the process I went through I will
do so. I have many hundreds of pictures to add.
Whatever your vehicle is, whether it is a turbo car or NA or a Toyota or other manufacturer, I hope that the automotive information on this page is of benefit to you as you take the path of modification and upgrade on your car.
Toyota JZX90 MarkII TourerV.