scblackout

iTrader: (2)

About a month ago I purchased a 98 auto tt torsen pumpkin and finally got around to installing it today. Everything went smoothly, we took out the old yolk from the sc pumpkin and used it on the supra pumpkin so that the 'flange?' holes line up properly. We used 75x90 diff fluid plus a small bottle of lsd anti squeel is what I think it was called. We also replaced the internal axle gaskets as well as the 'yolk' gasket. Prior to install the diff spun freely with no apparent binding anywhere.

The problem I have noticed is that in first and second gear it sounds a little 'clunky' and not so solid, especially when trying to do any type of 'pull' over 2500 rpm.

While I read a lot of threads on the upgrade first, I just wanted to ask if there is anything other than changing the yolk that is needed for the upgrade and to ask what might be the cause of the loud clunking in 1st and 2nd gear.

ideas?

*I don't need to change the axles do i?

HiPSI

iTrader: (2)

That rear yoke you removed and reinstalled sets the backlash settings for the gears. It has to be perfect or the gearing will bind or be way off. Did you just swap the flange and crank it back tight ? That rear nut has to be torqued correctly to mesh the gearing properly.

KahnBB6

iTrader: (5)

^^ This is VERY important. The MKIV and SC TSRMs have the same procedure for this, although I'd only go by the MKIV TT Auto diff torque specs just to be safe (though I can't imagine them being different from any other similar 200mm GS or SC differential). To do it you have to use a dial-torque wrench because a more common click-type torque wrench isn't accurate the way the steps are specified by Toyota.

If you get the torque setting wrong it can upset the delicate mesh tolerances of the ring gear and pinion gear inside the differential. scblackbout, I'd get a driveline shop to look at yours sooner rather than later if you are having consistent trouble.

scblackout

iTrader: (2)

Thank you for the iinfo. Yes I watched the tech take the yolk off the old one, add a new front seal to the supra pumpkin and then simply pound on the sc yolk. I did not stick around to watch the put the nut on and torque it. I can say now it is highly apparent they didn't do this right and I will show up first thing to let them know the proper procedure. This is not the normal shop I use, just a few local guys in a shop and I figured they would have no problem simply changing a pumpkin.

Hopefully it was more on the loose end vs. the binding so that if any damage was done in the 2 mile drive that it is minimal.

The closest info I found was to torque the nut very slowly between 4.3-6.9(ft/lbs) on another thread here. As no one disputed it I am currently assuming that is correct.

HiPSI

iTrader: (2)

They need the Toyota manual to follow. This thread has a lot of good pictures and also has the manual images.

http://www.supraforums.com/forum/sho...f-Build-Thread

The problem is that since all that was taken apart, there really is no way of knowing if the gear is right without measuring the backlash and using some red paint on the gears to make sure it's meshing with the pinion correctly.

Ali SC3

iTrader: (10)

take it to a better shop, try a 4x4 shop or a shop used to setting up rear diffs.

Shayy

iTrader: (1)

I recently purchased a TT auto diff and am afraid to install it because of all these complications. I may sell it to avoid potential problems.

HiPSI

iTrader: (2)

It's honestly pretty straight forward, unless you really don't want to mess with it then like suggested above get a drivetrain specialist or 4x4 place to set the torque back on the nut.

Some people mark carefully the position of the nut on the companion flange thread, and count the number of 360 deg turns it takes to remove the nut which when installed back on if followed should be spot on as before.

KahnBB6

iTrader: (5)

Here is the 1993-98 MKIV Supra TSRM's "Driveline & Axle" subsection. Pages 61-81 concern everything differential related. Please note that this covers not only the 200mm NA and TT Auto differentials but also the 220mm TT V160 differentials as well. Look for specific notes in the instructions that say "Except 2JZ-GTE M/T" or things to that effect as the specs for the 200mm TT Auto (and NA and SC300/400 and GS differentials) will be slightly different than the big 220mm diff.

scblackout

iTrader: (2)

I believe that I found the problem.

I have a 96 5sp and the pumpkin that I purchased here was missing one of the axle stubs so we took the stub from my na pumpkin and installed it into the auto pumpkin.

Well it seems that the axle stub will not 'lock in place' properly as it is not the right length. I found a lot of people having this problem on the supra forums when they switch from torsen to trd where the stubs pop out under wheel hop.

I called toyota and they do not have access to a new axle stub from a 98 auto tt so that seems to not be an option.

So does anyone who has done this swap have any good ideas?

i.e.
Would it make any difference if I took the internals out of the auto pumpkin and installed them into my sc pumpkin?

Are there other axle stubs and axles that would solve this problem?

.... I sent a pm to the seller to see if by any chance he still has the missing axle stub but to early to hear back from him yet... fingers crossed.

KahnBB6

iTrader: (5)

scblackout,

This is a new one on me I'm sorry to say. I have heard of this in rare cases but I am not familiar with the details of axle length differences. My 1993 model fit the MKIV TT Auto diff casing with my SC axles without issue. All of these pumpkins are 99% identical... or are supposed to be.

To your second question, yes, you absolutely can swap the 3.769 ring, pinion and Torsen LSD into your NA pumpkin with another full rebuild. You would only lose the cooling fins on the TT pumpkin. I'd hate to see you go through that if it weren't needed, though. There is still the question of whether the companion flange was swapped on to the correct spec.

What year range axles do you need to swap in to correct this? Only 1998 MKIV TT Auto axles or will 96-98 do?

scblackout

iTrader: (2)

I did switch the companion flange so that it would mate to the driveshaft.

As to the axles I am not sure yet. Everything bolted up just fine in the car. It is just that the sc axle stub won't seat into the carrier properly. I am working on sourcing a few options this weekend. Once I come up with a working combination I will post the results.

From what I have learned it seems that for a short time in 96 they produced the 5sp with the 'short' collar axle stubs (just like auto tt) yet the end of the stub with the clip lock is to long to lock in place. There is a great thread on sf related to everything diffs, and this issue has been raised in the past, though a bit of a unicorn scenario.

1A1

You also don't need the friction modifier for the diff fluid. Drain the diff and fill it up with regular 75/90 (or synthetic).

steve

KahnBB6

iTrader: (5)

scblackout, if you have that SF forum link handy, post it here. I'd like to see it too. 1996 was a transition year for the Soarer and Supra in both the Japan and the US so this would make sense. Maybe we can narrow it down a bit.


^^ Yes. Torsen LSDs don't require anything but normal 75W-90 gear oil. Any blend with a "friction modifier" should NOT be used. That's for clutch-type LSDs only. I prefer Redline Heavy Shockproof or Mobil1 with my Torsen.

scblackout

iTrader: (2)

http://www.supraforums.com/forum/sho...erential-Info!

Here is a pic of my 96 5sp diff with one of the axle stubs attached where you will notice it is skinny compared to other sc axle stubs. It is the same size on the outside as the supra auto but the inside does not clip in. I'll get comparison pictures of the removed axle stubs tomorrow when I see the car at the shop.