Hello!

i looked in the search function, but i found no answer, i hope you can help us.

My friend have a 92 SC300 M/T and will install a Supra NA diff with 4.08 ratio.

All fine, but the flange to the flex disc is different!

Is this normal?

here pictures from him:





Flange LSD Supra have 111mm


Flange OEM open diff have 101mm


Need he a other flex disc (coupling) or only change the flanges, like this thread link to change flange

But it is normaly not difficult to have the correct Nm for the bearing? or is this separat to adjust on the diff?

My Supra TT LSD (4,67) have a flex disc with all holes 111mm. Is this plug´n´play on my 97 SC400 or must i also modify my diff for fit?

I taken 2 pictures of the flex disc from my SC400:



have somebody a SC400 diff to measure the distance between the holes like the pictures obove?

Thanks for your help!

greets from Austria

Tom

 

I believe you swap ur original flange onto the new unit.

 

HY!

Thanks for your answer.

You think, its not a problem for the bearing? I read only its plu´n´play to change the LSD on the SC, no one wrote he must modify the flange or change the flex disc

thanks

Tom

 

That is a good question Boergy. The rear diffs I have set up before used a crush collar to set pinion preload. Simply swapping the front yoke on those diffs is not a good idea because you lose the preload setting.

I would like to hear the answer to your question as well. I am willing to bet people just tighten it down and go, even though there is no telling what the preload is, and how long it will last without issues.

 

this is my worry as well
im in the process of swapping a auto tt into my sc and am worried about swapping the companion flanges

 

Hello!

So..i looked yet under my SC, i have also 101/101mm flex disc from hole to hole, ****.

Ok..i see. its 2 different flex discs only? the 101/101 from the SC and the 111/111 from the Supra? I looked in the ******* and found only 2 Flex Discs. Or gives OEM flex discs in 101/111mm?

Thanks guys for your help.

greets

Tom

 

everyone just swaps the flanges, I have never heard of a failure due to swapping that flange, and literally everybody does it, check supraforums, these diffs are beefy they can take tons of abuse.

 

Yeah i had to swap my flange on a 97 sc300 it measures the exact same on mine. Very easy to do.

 

HY!

Thanks for your answer! How much Nm had you fixed the flange? or with the impact wrench?

No problems with noise from the diff? all ok? how much miles have you driven with the lsd?

Thanks

Tom

 

you cant just torque the nut to a certain ft/lbs, it doesnt work like that. The more you tighten the nut the further it pulls the pinion away from the ring gear. if the nut is either too loose or too tight it can throw the alignment between the pinion and ring gear off.

you have to measure the amount of PRELOAD it takes to get the flange to start turning.

you have to have a BEAM type or DIAL type torque wrench. like this: http://www.sears.com/shc/s/p_10153_1...5&blockType=G5

after you swap the flange you VERY VERY VERY slowly tighten the nut in increments. then check to see how much force it takes to turn the flange with a beam type torque wrench. on a used diff the preload should be between 4.3-6.9in/lbs

 

Actually, I have never seen the crush collar affect pinion depth. Usually, pinion depth is set with a shim behind the pinion bearing. The crush collar does nothing but preload the pinion assembly.

If you overtorque the crush collar, you will have excessive bearing preload, but the pinion depth should not change.

If you undertorque it, you will have inssuficient preload which may allow the pinion to move laterally in extreme cases. So I guess you could say that too little torque could allow the pinion to move in relation to the ring gear. it would allow the pinion to move TOWARDS the ring gear.

Either case is going to cause wear and eventual failure.

 

The first time I had this done, I took it to a Toyota/Lexus master mechanic. He just swapped them out and set the new one down to the same amount of threads showing.

This last time I did it 3 days ago I had another mechanic do it for me who has done differentials before, and he didn't check preload either.

I have the Lexus FSM here that shows the proper procedure for checking preload so maybe I'll post it up later when I get home.

The GTE flange is slightly larger as well.

 

It's a large photo

http://img.villagephotos.com/p/2003-...2/DSC01827.JPG

 

Both mechanics had to use the impact for removal and installation.

I drove on the lsd diff after swapping flanges the first time for 2 yrs daily driving, maybe 20k miles.

No problems and no noises. I used Amsoil severe gear fluid as well.

This time I'm using an open diff with non synthetic castrol hypoy gear oil, no noises so far, the diff is smooth going down the highway.

 

HY!

Thanks for all your answers!

My friend will change the flange, i changed today the LSD in the SC pumpkin i prefer the original ratio, not the longer from the Supra

greets

Boergsn