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I was gonna say, the c clips can certainly get bent and do next to nothing. I have definitly run into a few rear ends on these cars where one or both of the stubs would frequently pop out of the diff. Besides shit getting into the diff, it doesn't really cause any problems though as the stub can only come out about an inch when bolted to the A arms.

Totally forgot to check this this weekend. Text me next saturday and I will remember
 

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Hey All,
I was chatting with the well known Zuk of Gearinstalls about the MKII true trac swap. He has his reservations about it, in his first email he stated " The Truetrac is known to have issues with the clip not holding and the CV wanders out about 1/4" and leaks oil on the driveway. " I was wondering if this is related to what you guys were discussing about different axle stubs or if this was the input CV he was speaking of.
Also I brought up the need to shim the carrier bearings with the use of the 644 diff and he stated
"Yes, the master kit is very good about having the correct 50mm carrier bearings. I'm familiar with the shimming of the carrier bearings and that is not the fault of the TT unit it is the fault of the bearing kit. There are 3 different 45mm carrier bearings that are sometimes included in the kits....only one has the correct offset to use oem washer plates. Not an issue with the 50mm bearing kits though (90366-50006). Those are in the master kit. "

Thought this might be relevant info for this thread. He also uses Nitro Gear master kit but I assume he switches the bearings to the 50mm ones as the rear 7.5" toyota kit on their site states it comes with 45mm bearings.
 

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The fitment issue was more due to the 'width' of the truetrac unit as compared to the OEM center section. 50mm bearings are always used with the truetrac units. Any I have built (aside from Dean's rebuild) have been possible to setup with the stock selection of side washers.

As for the stub shafts, the ones used in an open diff and factory LSD are different. The factory LSD shafts have the snap ring not as close to the end, so they don't properly engage in the truetrac to lock the shafts in really well. I haven't had issues, but the clips on mine are pretty stiff.
 

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Discussion Starter #244
I put mine in a non lsd 3.727 diff, so never had issues with the stubs coming out. Daily drove and abused the car for YEARS!!! As for the bearings, you must use the 50mm ID bearings as the 45mm ID stock bearings will not fit the Tru Trac lsd. It was designed for the front diff on 4x4 Toyotas, which have 50mm ID bearings. I didnt have issues shimming the carrier bearings for the proper offset and preload either, though I didnt have a kit. I just had a few busted stock diffs to take shims from. I used genuine Toyota bearings, so IDK if maybe aftermarket bearings have issues with their offest? Never heard of the issue at all before you mentioned it Texasissouth
 

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...I didnt have issues shimming the carrier bearings for the proper offset and preload either, though I didnt have a kit. I just had a few busted stock diffs to take shims from. I used genuine Toyota bearings, so IDK if maybe aftermarket bearings have issues with their offest? Never heard of the issue at all before you mentioned it Texasissouth
Page 12-22 show disco and fiend talking about how the 644 had a shorter case and required extra shimming, then page 23 funky cheeze details a way to shim the carrier bearing instead of using thicker shims from the yukon kit.

As for the different stub axle, looks like I need to check if my parts car diff is open or LSD. I'm pretty sure it's gonna be LSD so hopefully the short stubs won't be an issue
 

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Discussion Starter #246
The non lsd has the stubs needed from what everyone has posted. The non LSD are the stubs I am using without issue. I didnt notice them mention the shim issue. im guessing they got the rwd application that didnt exist when I bought mine, or maybe the design changed slightly when Eaton bought Detroit Locker. I bought mine a LONG time ago. lol
 

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It would seem the carriers that are 'short' and need shimming under the bearings to use the factory carrier shim range are rare. Most Truetracs will fit fine with the factory shims. I think maybe just a factory defect or right on the end of the tolerance range. The FWD carriers in the IFS trucks use the same shim pack.
 

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Back from the dead again. I just bought the 644 and about to order all the bearings and shims. I might buy the thicker youkon shims just to be sure it can be installed without issue. My car has the factory lsd. Will I need the open diff stub Axel's? If so does anyone have a set and willing to ship?
 

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The open diff stub axles are preferable as they do not pull out as easily with the truetrac installed, the C clips on them actually engage past the splined center of the LSD unit. That being said, lots of people have been using the LSD axles with truetracs and it is rare for a stub to get pulled out of the diff while the vehicle is being driven, except if the C clips are very worn out. A good set with stiff C clips stays in quite well and there shouldn't be much pulling force on the shafts as the CV shafts have a plunge joint built in.

I tried looking for a set of open diff stub axles for a year or two without much success. Just sticking with my LSD stubs for now.
 

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Thanks for the reply! I will look to see if the tsrm has the size of c clips so I can get some new fresh ones. I am hoping to get ahold of a set of non lsd stubs and just have my lsd stubs as back up. Have you done the install with the 644? I have read through this thread a few times but I think I am going to send mine to a local guy who has experience with true tracs and rebuilds tons of diffs.
 

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The retaining rings are still available from Toyota for a little over a dollar each. P/n 90521-29002
 

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So who is the best source to purchase the tru-trac center chunk from?

summit?

instead of reading a bunch of stub axles issues was curious if anyone may have a link or hell even a full diff already together they would sell im in a purchasing mood and my Ol red is in need....


Destroyed it this past weekend after a small burnout at the track....
Just got her back from victory motorsports where she came back to me make 442hp with 382 tq (7mgte 91mm turbo,r154, act extreme hd clutch, ms3x standalone)
and i guess the diff didnt like it lol......

Needing to get this back together so i can go play more lol
 

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Discussion Starter #254
Just searched and cheapest I found it was only $5 cheaper than Summit, and it was a company I never heard of. I would go with Summit. Dont forget you need carrier bearings with the 50mm ID. 89 4wd 4 runner front carrier bearings is the application.
 

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90368-50006 are the carrier bearings you need. I have struggled with any aftermarket source for these, but the Yukon gear bearing and seal rebuild kits for 4 runner/puickup standard rotation 7.5" FRONT diffs will work, except for the side seals which you can get as Timken 2009 or Timken 2009S

*EDIT* make sure the Yukon kit is for a V6 4 runner / pickup, standard rotation front diff so it has the 50mm carrier bearings.
 

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Good to know Thanks!!

90368-50006 are the carrier bearings you need. I have struggled with any aftermarket source for these, but the Yukon gear bearing and seal rebuild kits for 4 runner/puickup standard rotation 7.5" FRONT diffs will work, except for the side seals which you can get as Timken 2009 or Timken 2009S
 

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Make sure the Yukon kit is for a front diff from a V6 truck so it has the 50mm carrier bearings. I updated my post above.
 

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Is there any reason to purchase new gears for a trutrac build?
Mine have 200K (miles), but had been all on the stock 5M. Not the only owner but they have been fine for the last 30K I've had the car. 0 noise, 0 issues.
Now has 400+HP on a V8, needs a solid spacer upgrade, and will do the true trac while I'm at it. Just wondering if it's worth the risk in still using the older gears since I'll have it open and the increased HP/Torque. Would rather not have to open it back up, but also looking to use the money wisely and where it makes sense.
Just used for fun right now and possibly getting into some street/strip/autoX one day.
 

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Just reuse them unless there is some obvious damage to them.
 

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If you are running 4.10s or shorter, a brand new set of gears might not be a bad idea. Otherwise keep what you have.
 
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