TRD LSD questions

[Will-I-Am]

Hi Guys.

Been searching the forums for some answers but need to get some specific answers

Just some quick questions about the TRD Diff i recently bought of here. Cant get an answer from the guy who i bought it from (maybe he is away for a long time or something)

1: Installation. How hard is the installation. My sponsor has a workshop and has been working on toyota engines allot but not on gearboxes / installing diffs etc. Any thing we have to be careful of or keep in mind?

2: 1.5/2way, i have read that the yaris diff from TRD is 1.5 only but can't confirm it. Is this true? Is it a plate diff or a helical? Lots of info on the internet but all are telling something different haha

3: Brake in procedure? He said the diff was brand new so i guess it has a brake in procedure?

Thanks a lot guys!

[xnamerxx]

Originally Posted by Will-I-Am

Hi Guys.

Been searching the forums for some answers but need to get some specific answers

Just some quick questions about the TRD Diff i recently bought of here. Cant get an answer from the guy who i bought it from (maybe he is away for a long time or something)

1: Installation. How hard is the installation. My sponsor has a workshop and has been working on toyota engines allot but not on gearboxes / installing diffs etc. Any thing we have to be careful of or keep in mind?

2: 1.5/2way, i have read that the yaris diff from TRD is 1.5 only but can't confirm it. Is this true? Is it a plate diff or a helical? Lots of info on the internet but all are telling something different haha

3: Brake in procedure? He said the diff was brand new so i guess it has a brake in procedure?

Thanks a lot guys!

1. Hard, if you don't have the means to rebuilt a manual transaxle I wouldn't attempt it.

2. You don't want a 2 way diff, as 2 way has full lock on both accel and decel. I would doubt the TRD diff is a 1.5 diff being its a helical, but there will always be some form of friction from the gears so its probably a 1.25 or 1 way diff, being that your car is FWD you don't want lock on decel since it would prevent the car from turning. For the most part you don't want a clutch type LSD on a fwd car unless its a salisbury type ie OSGiken\Kaaz because they have accel clutch packs and decel clutch packs.

3. Given its a racecar theres not much you can do with break-in aside from take a few laps a little easy but there isn't really any wear in that needs to occur so I wouldn't worry about it so much.

[Will-I-Am]

ok. i have the 41301-AW004 Diff from TRD

it says on the website of TRD

■ The TRD mechanical LSD is 1.5-way selective, and can optionally be switched over to a 2-way without any additional parts. (It can only be 1.5-way on Vitz models and 2-way on FR vehicles.)
With the 1.5-way, the LSD functions most during acceleration, and is weaker when not accelerating. (The 1.5-way is designed for novices, since vehicle control becomes more difficult when the engine is used to brake.)
With the 2-way, the LSD functions when not accelerating as well, providing excellent vehicle control under a variety of conditions.

So the TRD Vitz LSD is a 1.5

also it states:

■ Because the limited slip capacity is provided using a number of clutch plates, it exhibits a direct, reliable LSD effect.

So not a helical but plates? like the kaaz diff?

[xnamerxx]

Its not a clutch type diff its a helical diff. If you open the box of the TRD you'll see the hypoid gears which looks like the picture on the left, the clutch pack type is shown on the right.


Don't read the blurb its not accurate from the catalog as its not accurate with all diffs they sell.

[Will-I-Am]

ah that makes sense allot! Just looked at my diff and i can see the gears indeed. so its a helical. They don't need lots of service as a plate diff does right, because of the wear on the plates?

Sooooo looking forward to having it in and trying it out on the track but not looking forward to the install haha. I thought the installation was removing the bell housing, removing the diff and swapping final gear ring but its allot harder then that you say. Thats because on some pictures i saw the diff is the first thing you see when you open the gearbox haha

[xnamerxx]

Unless you break the diff I doubt you'll have to crack it open.

I'd love to race over there sometime, seems like there is a bigger small car scene vs over here. Being in NL you've got some pretty awesome tracks within a few hours distance. Let me know how the diff ends up working out, I'm pretty curious how the TRD unit stacks up.

[CrankyOldMan]

I'm in the process of (finally) installing my Quaife helical and it has been a very fun experience. My first advice is to get a copy of the gearbox section of the manual over on microimageonline.com and give that to your tech/mechanic. That way he can make sure he has the right tools and supplies to do the swap and doesn't have to guess at which bolt is still holding the damned thing together. You can also make sure you have all the non-reusable parts on hand before starting.

Setting the preload for the LSD isn't covered in our manual, but it is covered in the Celica and MR2 manuals. I'll have to take a look and see if I can find the pages I followed... You basically put the diff and the pinion shaft in the casing, bolt it together, put the retention nut on the pinion shaft and measure the break-free torque on the pinion. You'll need a 27mm socket and a torque wrench that can reliably measure in-lbs of torque.

The hardest part for me will be the removal and replacement, but only because I've built my new gearbox from 4 different salvaged units and haven't had to take the front of the car apart yet. Having access to a car shop with a lift will make a HUGE difference in the difficulty.

[Will-I-Am]

Originally Posted by CrankyOldMan

I'm in the process of (finally) installing my Quaife helical and it has been a very fun experience. My first advice is to get a copy of the gearbox section of the manual over on microimageonline.com and give that to your tech/mechanic. That way he can make sure he has the right tools and supplies to do the swap and doesn't have to guess at which bolt is still holding the damned thing together. You can also make sure you have all the non-reusable parts on hand before starting.

Setting the preload for the LSD isn't covered in our manual, but it is covered in the Celica and MR2 manuals. I'll have to take a look and see if I can find the pages I followed... You basically put the diff and the pinion shaft in the casing, bolt it together, put the retention nut on the pinion shaft and measure the break-free torque on the pinion. You'll need a 27mm socket and a torque wrench that can reliably measure in-lbs of torque.

The hardest part for me will be the removal and replacement, but only because I've built my new gearbox from 4 different salvaged units and haven't had to take the front of the car apart yet. Having access to a car shop with a lift will make a HUGE difference in the difficulty.

Thanks for the info mate. If you could get your hands on the preload info that would be really helpfull!

[Will-I-Am]

so a mate of mine is going to install the diff. He is a gearbox builder so wont be a problem. Already ordered a LSD install kit from Monkeywrench with new bearings and have a spare gearbox. The only thing we need to know is the preload on the diff. anyone know how much?

cheers!

[CTScott]

Originally Posted by Will-I-Am

so a mate of mine is going to install the diff. He is a gearbox builder so wont be a problem. Already ordered a LSD install kit from Monkeywrench with new bearings and have a spare gearbox. The only thing we need to know is the preload on the diff. anyone know how much?

cheers!

Preload (at starting):
New bearing:
0.78 to 1.57 N*m (7.95 to 16.0 kgf*cm, 6.9 to
13.89 in.*lbf)
Used bearing:
0.49 to 0.98 N*m (5.0 to 10.0 kgf*cm, 4.34 to
8.67 in.*lbf)

[CrankyOldMan]

The trick with the LSD is that you have to measure on the pinion shaft. Basically, you install diff and pinion shaft, put in all 16 case bolts (torque to spec), put the retention nut on the pinion shaft, and check the torque with a 27mm socket. You calculate the torque by dividing the above number by the final drive ratio. If you're still stock, it's 3.722. That means you need to be between 1.85 and 3.73 in*lbf to start rotation on the pinion shaft (with new bearings).

I've got an extract from the MR2/MRS manual that has the detailed procedure around here somewhere...

[Will-I-Am]

found a C56 gearbox manual and it says that you only have to preload when replacing the tapered roller bearing and outer race of the differential case but mine already has new rollers?



or am i having a brain fart and has that got nothing to do with it?

[CrankyOldMan]

You still want to check it. Too much and the bearings will grind down, too little and it will bounce back and forth. Neither are good. I would guess that those are the original bearings, so use the "used" preload values instead. In all likelihood, the outer races and spacer that are in your gearbox will be fine, but it's easier to change the spacer now.

[Will-I-Am]

bearings look brand new. The guy said its a complete new diff and never installed. but always good to double check these things

[CrankyOldMan]

Strange. Do you have the new races too, or just the old ones in your current gearbox?

[Will-I-Am]

ive got a complete spare gearbox with the old diff in it

i ordered:

http://www.monkeywrenchracing.com/pr...roducts_id=861

but hence this diff has got new bearings in it, i didnt know if i needed this kit but just to be sure i ordered it.

[CrankyOldMan]

I ordered the bearings separately and then the OEM gearbox gasket rebuild kit. I didn't use all of the seals, but it comes with all of the rubber seals for the whole gearbox. As long as the old races are in good shape--smooth, clean, etc--then you should be OK to use them again, as long as the preload is right.

[Will-I-Am]

ok thanks! We will deff check the preload. thanks for the help