Myth Settled: 8.4, V6, 4cyl, ALL 8"

[Brian Ellinger]

Posted this up on TTORA. Just copied and pasted:


There is a lot of misinformation out there on these diffs we've all got. These post is ment to clear the air, with actual facts and measurements taken, NOT hearsay. 5 diffs, Im concerned with:
4cyl (from 79-95 4cyl rear diffs, fronts in 79-85)
Early V6 from 88-95 rears in V6 trucks, and 86-87 rear trubo trucks
E-locker rear
High pinion front
Rear 8.25 or whatever (non-locking, taco rear diff)
NEWS FLASH, these are ALL 8" ring gears. The early 4cyl, is the weakest, with the smallest bearings, least ribbing, and pathetic carrier.

The early v6, used screw in adjuster for backlash and carrier bearing preload. It has a 4 pinion (better) carrier, bigger bearings, and more casting in the case.

The E-locker rear uses the same exact gear as the early V6 does, 10 bolts, 8" ring gear. The bearings are all the same, except the drivers side carrier bearing is much large for the shift mechanism.

The high pinion, from the front of fj80's are just a high pinion v6, or high pinion e-lock. Bearings are identical with low pinion versions.

Now the MYTH cleared up. The 8.25/8.4, whatever is not. It is a 8" gear. The casting is better still. The carrier bearings are shimmed, rather than screw in adjusters. The ring gear has 12 bolts instead of 10. Also, the carrier bearing caps are connected with "girdles" and are cast as one piece. This diff I will simply call the late model v6. The pinion shaft is larger, the bearings are slightly lager and the casting is beefier than earlier versions. However, THE RING GEAR IS NO LARGER THAN EALIER 8" DIFFS!

Just so you all know what you are dealing with with these axles.

[Bones]

Thanks for the TECH, that's good to know.

BTW, I'll get that 8.25/8.4 or as you call it "the late model v6" diff shipped off tomorrow for ya.

[4RnrRick]

Thanks for the [b]myth buster[b]!!

Its been added to teh FAQ.

[rusted]

Originally posted by Brian Ellinger

Now the MYTH cleared up. The 8.25/8.4, whatever is not. It is a 8" gear. The casting is better still. The carrier bearings are shimmed, rather than screw in adjusters. The ring gear has 12 bolts instead of 10. Also, the carrier bearing caps are connected with "girdles" and are cast as one piece. This diff I will simply call the late model v6.

If you're clearing up 'myths' or misnomers, might as well clear this one up and not start a new one.

It's not a late model v6, since it's used on 4cyl tacomas. Call it the Taco rear or the Tundra rear. Calling it a v6 is just another misnomer.

[surlynkid]

Originally posted by rusted


If you're clearing up 'myths' or misnomers, might as well clear this one up and not start a new one.

It's not a late model v6, since it's used on 4cyl tacomas. Call it the Taco rear or the Tundra rear. Calling it a v6 is just another misnomer.

no respect at all. it was first found in the T100. let's call it a T100 diff.

[crashinaz]

And of course all of these 8.25's and 8.4's that are actually 8's aren't ACTUALLY even 8's... Oh the humanity!

[85TrailToy]

I never thought of this before... but will the Taco/T100 diff bolt into the earlier housing?

[ErikB]

Originally posted by Brian Ellinger
The 8.25/8.4, whatever is not. It is a 8" gear.

I've been saying this for quite some time now!

The T100 was the first to use it (since '93). All of them- 2wd, 4wd, 4cyl. and V6.
The '95.5 Tacoma's were the next, then Tundra's, Sequoia's, etc.

Since this T100 diff was Toyota's answer to a "full size" truck diff, and since most people don't know much about T100's, and since not all Tacoma's came with them, I just call it a Tundra or T100/Tundra diff. Or I guess you could call it a V8 diff...?

4cyl and V6 diffs have a lot of simlarities and swappable parts.

The T100/Tundra diff is 8" size-wise, but nothing else is the same or swappable.

[ErikB]

Originally posted by 85TrailToy
I never thought of this before... but will the Taco/T100 diff bolt into the earlier housing?

NO!

http://home.4x4wire.com/erik/diffs

[Brian Ellinger]

True, Not a late model V6, maybe just a late model 8" diff then.

And we could call it a T100 diff, but now its in more than just those. Maybe the "BIG 8"???

Nope, not 8";s. Technically these are supposed to be measured on ring ring bolt circle diameter...Hmm, that makes this a 6"

As far as fitting the earlier housings, nope. Few problems:
The "girdle or birdge" wont clear the diff cover (hammer fix?)
The studs are 10mm instead of 8mm.

The bolts pattern is significantly different, so redrilling and tapping is not an option. However, drilling in a completely new pattern would be possible.

Also, the hole in the housing isnt large enough to accept the newer diff either.

So yeah I guess you could, but it'll be some work.

[rusted]

Originally posted by Brian Ellinger
True, Not a late model V6, maybe just a late model 8" diff then.

And we could call it a T100 diff, but now its in more than just those. Maybe the "BIG 8"???

Nope, not 8";s. Technically these are supposed to be measured on ring ring bolt circle diameter...Hmm, that makes this a 6"

As far as fitting the earlier housings, nope. Few problems:
The "girdle or birdge" wont clear the diff cover (hammer fix?)
The studs are 10mm instead of 8mm.

The bolts pattern is significantly different, so redrilling and tapping is not an option. However, drilling in a completely new pattern would be possible.

Also, the hole in the housing isnt large enough to accept the newer diff either.

So yeah I guess you could, but it'll be some work.

Besides those differences, is there any other difference btw the Taco/Tundra/T100 housing and the older ones? I know it varies in width, but is it THICKER or in any significant way mechanically different?

[flecker]

Hey... I know! Let's just call them "Toyota Diff Housings that Vary"

[Brian Ellinger]

Originally posted by rusted


Besides those differences, is there any other difference btw the Taco/Tundra/T100 housing and the older ones? I know it varies in width, but is it THICKER or in any significant way mechanically different?

No, all the housings we've chopped up(and thats a LOT) are all 4.5mm/.188 thick steel "tubes". That includes both taco rears, an early, a wide, and a t100, and front housings.

[eep]

What are the differences in the axle shafts between all of these? splines, diameter, length...

will the shafts from a 8.25 axle work with a V6 3rd?

[4RnrRick]

Some more info from the FAQ:

Differentials – Gearing

Gearing..... with a 4 banger and single case
stock 3.96 or 4.10= 31 or smaller tire
4.88=33 inch tire
5.29= 35 to 38 inch tire.
5.71= NOT RECOMMENDED FOR REAL OFFROAD USE

Originally posted by DSI
----------------------------------------------------
83-older 4.11 diff's are 37/9 and are 8in 4cyl style diff's, in 84 they switched th the 41/10 ratio, any time you have more teeth to a pinion the stronger the diff will be, reason being: more tooth contact/more teeth contacting the ring gear at one time.
This is the same reason 5.71's are very weak, 6 teeth, 5.29's have 7, 4.88's and 4.38's have 8, 4.56's have 9 and 411's have 9, 410's have 10, and 390's have 10
----------------------------------------------------

Originally posted by TNToy
----------------------------------------------------
If you have the axle code of your vehicle, it is easy to find out what size differential, what ratio, and what pinion set-up you have. This will also help if you are hunting for a particular unit off another vehicle. The axle code is in the vehicle ID plate under the hood or drivers door. The axle code is 4 digits: a letter followed by 3 numbers.

Example: F372 = 7.5" 3.58 final ratio 2 pinion

1ST DIGIT R&P SIZE 2nd/3rd Digit R&P RATIO 4th DIGIT PINION SET-UP 
A 	138mm 	O1 	3.30 	2 	2 pinion 
B 	145mm 	O2 	3.36 	3 	2 pinion LSD 
C 	6.25" 	O3 	3.55 	4 	4 pinion 
D 	6.62" 	O4 	3.56 	5 	4 pinion LSD 
E 	7.1" 	O5 	3.70 	  	  
F 	7.5" 	O6 	3.89 	  	  
G 	8.0" 	O7 	3.90 	  	  
H 	9.0" 	O8 	4.11 	  	  
J 	9.25" 	O9 	4.22 	  	  
K 	9.5" 	10 	4.38 	  	  
L 	10.5" 	11 	4.44 	  	  
M 	12.5" 	12 	4.63 	  	  
N 	13.5" 	13 	4.79 	  	  
P 	14" 	14 	4.88 	  	  
R 	162mm 	15 	5.13 	  	  
S 	6.38" 	16 	5.29 	  	  
T 	6.7" 	17 	5.60 	  	  
U 	6" 	18 	5.71 	  	  
V 	10.6" 	19 	5.83 	  	  
W 	15.5" 	20 	6.17 	  	  
X 	142mm 	21 	6.67 	  	  
Y 	158mm 	22 	6.78 	  	  
  	  	23 	6.83 	  	  
  	  	24 	7.64 	  	  
  	  	25 	4.56 	  	  
  	  	26 	5.57 	  	  
  	  	27 	3.36 	  	  
  	  	28 	4.30 	  	  
  	  	29 	4.10 	  	  
  	  	30 	3.73 	  	  
  	  	31 	3.91 	  	  
  	  	32 	6.59 	  	  
  	  	33 	7.50 	  	  
  	  	34 	6.78 	  	  
  	  	35 	7.64 	  	  
  	  	36 	4.78 	  	  
  	  	37 	3.58 	  	  
  	  	38 	3.42

Differentials – Info

General Toy diff info including identification with pictures.
http://home.off-road.com/~bibelheime...diff_info.html


Differential picture identification by 4RnrRick

Toyota 2 pinoin 4 cylinder 7 1/2" diff (27 spline) used on 2wd and some celicas



Toyota 2 pinoin 4 cylinder 8" diff (30 spline)



Toyota 4 pinoin 6 cylinder 8" diff (30 spline)



Toyota Land cruiser high pinion 8" diff (30 spline)



Toyota 4 pinion 6 cylinder 8" 3rd from a '96-00? 4Runner (30 spline)



Toyota 8.25 or 8.4 diff Taco / T-100 / Tundra (30 spline)






Originally posted by Drew Persson
----------------------------------------------------
Techies can read this. Newbies please skip to the next post, you'll only drive your local parts guy nuts if you try to talk to him about it.

Here goes: There's no such thing as "4cyl" and "V6" R&P.

"Uhhhhhh, say what Beavis?"

There are actually two types of R&P, let's call them "LPH" (Long Pinion Head) and "SPH" (Short Pinion Head).

- '79-'85 rigs have SPH gears and a "thick" inner pinion bearing designed for the 4cyl housing. All aftermarket "4cyl" R&P and inner pinion bearings are identical to these factory parts, that way the same part numbers will fit all '79-'95 four-cylinder rigs.

- '86-'95 four-cylinder and V6 rigs ALL come with LPH gears. However, to use LPH gears in a four-cylinder housing you MUST use the "thin" '86-'95 factory Toyota four-cylinder inner pinion bearing. If you use a "thick" aftermarket bearing (or a factory '79-'85 bearing) the pinion will be too deep into the mesh and won't work.

- SPH gears will fit V6 housings if you add a lot of inner pinion bearing shims. Precision Gear avoids having to use so many shims by offering an aftermarket LPH gearset for V6 housings.

- '88-'95 V6 housings must obviously use V6 inner pinion bearings, so there's no confusion here.

- Carrier bearings aren't an issue here either, just R&P. You need 4cyl carrier bearings for 4cyl housings and V6 carrier bearings for V6 housings regardless of year.

So what good does this do anyone? Say you have some used LPH gears collecting dust because you didn't think you could use them in your 4cyl housing. They're even the ratio you want, like the V6-only factory 4.56 or a set of Precision LPH gears (any ratio) your buddy traded you for a six-pack. Take your bad self over to Toyota and order a '86-'95 4cyl inner pinion bearing, and you're in business!

Note: The above does not apply to the somewhat rare "3rd type" of R&P, the factory 4.88's. These can only be used in the factory 4.88 housing. This housing is different than all the others, and won't accept ANY aftermarket R&P or factory gears of any other ratio. If you have one of these 3rds, it will be that way forever. Please don't sell this 3rd (or god-forbid an empty housing) to anyone without fully explaining what they are getting, think of the potential frustration.
----------------------------------------------------

[Pook]

Is there a factory 4.10 ratio 8.4" taco third?

[ErikB]

Nope- NO SUCH THING AS AN 8.4" !!!

This thread didn't teach you anything did it!?!?

But as for the T100/Tundra/Tacoma 3rd yes there are thousands of them. Generally V6 5spd 4x4's would the the first place I'd look if you need an application, but possibly others as well.

[FrankenToy]

Originally Posted by Pook

Is there a factory 4.10 ratio 8.4" taco third?

Pretty sure my factory '97 3.4L Taco (non-TRD) is this ratio.

[Landslide]

Originally Posted by Brian Ellinger

The early v6, used screw in adjuster for backlash and carrier bearing preload. It has a 4 pinion (better) carrier, bigger bearings, and more casting in the case.

Do you mean a 4 spider gear carrier?

More casting = it has more ribbing in the turd member for added strength.

I don't notice any difference between the early V-6 and the 22rte diffs either, I would assume Toyota just used the Turbo diff in the early V-6 rigs.

Their all junk anyway... reason I sold them and upgraded to D60's

[Aaronius]

Originally Posted by crashinaz

And of course all of these 8.25's and 8.4's that are actually 8's aren't ACTUALLY even 8's... Oh the humanity!

...and ' = feet where " = inches. It just gets worse and worse

[2manyprojects]

Originally Posted by Landslide

Do you mean a 4 spider gear carrier?

One and the same. When looking up parts, the vendors refer to them as 4 pinion.

[ErikB]

Originally Posted by Landslide

Do you mean a 4 spider gear carrier?

Well if you want to get picky, he meant diff CASE, not carrier.

The carrier is actually what we usually call the 3rd housing if you RTFM...

The gears can be called spiders or pinions (i.e. rack and pinion, ring and pinion, etc.). A pinion is just any small gear, usually one that engages a larger gear or a rack.

And just to keep things clear as mud... U-joints are also known as "spiders."

[SWAINBUILT]

Thanks for the Diff Code Chart 4RnrRick. I think this only works on the Jap built trucks though. It wont work on most of the 8.2/8.4/new V6/Big V6/6"/T100/Tundra "gasp" shim type V6/Tacoma/2 pinion V6 diffs!

I have a few other charts but they seem to be hit and miss on accuracy. I would like to see a consistent one.

[DRM]

I am gonna step out on a limb here and come up with a name for these diffs...

Tundra
T100
Tacoma



How about we go with:

"T-Series diffs" ?

Makes sense to me



Thanks for the FRESH TECH

[ErikB]

Originally Posted by DRM

Thanks for the FRESH TECH

Recheck the original post date... this thread is more than 3 years old!

Its thawed and reheated leftovers tech, but its still good!