F-series Trutracs.... new part number, different bearings, still works?

[takai]

Ok, i was about to grab a Trutrac for the F-series in the rear of the Supra, which according to the groupbuy that Witzl organised a while ago is part number: 911A342.

However, that part number doesnt seem to be made anymore, and its been superceded by the 911A644 diff, which is listed for the Tacoma front diffs. Looking at a few forums there seems to be a bit of uncertainty as to whether that fits in an IRS pumpkin. The Eaton catalogue (who make Trutrac) list the 911A644 as fitting a "“Small” hub bearing dia. 45 mm" wheras the 911A342 is listed as “Large” hub bearing dia. 50 mm - uses Toyota bearing #90368-50006. Although there is the note that another bearing allows it to be swapped...

Anyone know for sure?

[assassin10000]

If you need a 45mm bearing ID, the standard open diff should work (if MA61). Otherwise what car/diff is it going on?

Unfortunately, it looks like your a bit confused as the catalogue says the wrong thing. The Tacoma/Hilux IFS front uses the LARGER 50mm I.D. bearing. At least mine did when I had one installed in my truck.

17887/17831 | Carrier Bearing Cone/Cup w/o LSD (Toyota 90368-45002 for MA6x)
1.781" - I.D.
3.149" - O.D.
0.781" - Width
32010X | Carrier Bearing Assy w/LSD
1.969" - I.D.
3.150" - O.D.
0.787" - Width


Based on the dimensions I think you need Toyota 90368-50024 / Timken 32010X (50mm I.D.)


Andrew

[takai]

Thats the excerpt from the Eaton/Trutrac catalogue. From the previous group buy they bought the 911A342 which according to the really vague letters in the Trutrac catalogue is a 50mm bearing. However, taht assumes that the (t)(w) after the 7.5" IFS designation for the 911A342 refers to the bearing size, because i cant find anything about the (cw) designation next to the 911A644 entry.

Full catalogue available here: http://www.eaton.com/ecm/groups/publ.../ct_128302.pdf

[assassin10000]

Again... I think the catalogue might be wrong/misprinted.

Can you call/email whoever your getting it from and have them measure it so you know for sure what you need?

Andrew

[takai]

Yeah, ive emailed Eaton, Summit and JEGS. But given that its about 10pm im not expecting a reply any time soon.

[The Witzl]

hey Takai.... i found it was pretty easy talking to the guys at Drivetrain Specialists, and they knew what they were talking about.

I was in contact with a dude called Rich. Email was [email protected]
If that doesnt work, then [email protected] also worked to get through to someone knowledgeable.

..... it did help that i was buying bulk quantity diffs though!



EDIT - price is pretty good from them too - http://www.drivetrainspecialists.com...duct-2381.html

[takai]

Yeah, it appears though that the 911A644 has superceded the 911A342. Which could be a problem.

Ill give Drivetrain Specialists an email.

For the stock F-series IRS pumpkin what size bearing do they use? I remember there is a difference between live axle and IRS, but i cant remember if thats F series or G series, and which way it goes.

[assassin10000]

The IRS F-series of the MA6x uses the 90368-45002, which according to Timken is 17887 & 17831 bearing cone/cup. When I look at Toyodiy it shows them for both LSD & non-LSD.

Andrew

[takai]

Yeah, but that doesnt tell me if its a 45 or 50mm bearing. Even the Timken cattledog doesnt show what ID it is.

[assassin10000]

Found this from awhile ago. Looks like the older catalog may have been more clear. Still not much help, unless you switch to the 565 model if it's available.

http://www.celicasupra.com/forums/showthread.php?39772

Detroit has 3 versions of the 7.5" truetrac

2x FWD models:
911a445 (45mm carrier bearing I.D., uses stock open diff bearings)
911a342 (50mm carrier bearing I.D., requires 90368-50006 bearings)

1x RWD model:
911a565 (50mm carrier bearing I.D., requires 90368-50006 bearings)

IF they say the RWD model has stronger gears, I see no reason NOT to go to it. It should fit perfect. They are all 27 spline, 7.5" toyota rear carriers...

This site (shop is about 30 minutes from me) also shows the 565 for 2wd rear use.
http://differentials.com/Catalog/WCD..._2010_Page.pdf

Andrew

[takai]

Pretty sure the 911A565 is wider to suit the non IRS housing. More investigation needed

Edit, as per here: http://www.toymods.org.au/forums/showthread.php?t=14640

911A565 is the non IRS diff center, wider flanges, and wont fit the IRS pumpkin. Hence the FWD one is used.

[assassin10000]

I don't think it is, the IRS LSD's fit the Solid axles fine. The difference is usually the bearing size, not flange size. The flange size noted in your link was in regards to the Altezza Torsen and the crownwheel mounting, but a post right below it contradicts it...

What a PITA, wish their listing was clearer... is "(cw)" supposed to be "(w)" and a typo, and the "(v)" behind the part number in the wrong place/typo/placement.


Andrew

[assassin10000]

Hmm, more interesting finds. Looks like the 565 does fit.

http://www.celicasupra.com/forums/showthread.php?40847

http://www.celicasupra.com/forums/showthread.php?10188 (pages9-13)

post #84 - CLtoy

I spent some time on the phone with an Eaton tech (Barney) and he was surprised that we were using the 342 in our setup. Per Barney, the 565 was designed for legend race car rear-differential applications and by using the front (342) we lose 30% effectiveness and make it weaker by running the diff in a different direction than designed.

post #120 - CLtoy

as per previous post...eaton stated 565 for our rear application...mine is going together well ... just needing an adjustment in shims as to be expected

Also this:
http://www.customtacos.com/forum/sho...d.php?t=128016

I picked up a TrueTrac LSD from DMac, PN 911A565. The Eaton tag that came with it says it is for the rear (is not for 7.5" front diffs).

EDIT: plus, just had a thought. IF they changed the internal gears direction, why would they make a new case if they have one that already fits?

Andrew

[mullett]

Hi Takai, I'm not sure...but if you get one, I might be keen to, they seem a lot cheaper!

In other news, rabidchimp still have stock of the trutrack/MA61 upgrade with bearings etc...

-RM

[takai]

There is no information on RabidChimp as to which diff they supply unfortunately. Plus i already have new bearings, so its a bit overpriced.

Ill have to look into the 911A565 now.