9.5 third member casting strength difference (1 Viewer)

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Toyoland66

Toyoland66

Joined
Feb 3, 2004
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Location
Colorado
Is there any strength advantage, or other advantage to using a FZJ80 third member as a basis for building my differentials over using a FJ40 or FJ60 third member?

For those unfamiliar with the difference:

FZJ80 third member:
7907413580_b0b727cdc0_z.jpg


FJ40/60 third member:
TLC.jpg


The castings are different with different webbing. The R&P is the same but use a different install kit - I assume different bearings - can anybody clarify what the differences are (I think it is different ID on the carrier bearings i.e. different carrier)? Jantz engineering makes a load bolt kit for the 9.5" diff but I believe it is for the earlier casting based on these pictures:
http://www.pirate4x4.com/forum/15070202-post74.html

The reason I am asking is I am building a set of axles for my 40 (80 FF rear, 80/ 9.5" hybrid front) and have several spare FJ40 third members, but only one 80 third member (open). Would it be worthwhile to buy a second 80 third member to build off of?
 
I'd be curious too. I would expect the 80 diff to be stronger. From what I remember the 80 locking diff was a bit heavier than the 40 diff was.
 
The fj40 is 4.11:1 with a 37t ring and 9t pinion. The fzj80 is 4.10:1 with a 41t ring and a 10t pinion. I would expect the larger ring gear to have a minimal strength advantage. I doubt that the cast portion matters at all.
 
Stock gears, correct. I am regearing so that goes out he window. The aftermarket gear sets sold are for 40/55/60/62/80r, no difference.
 
Toyoland66 said:
Stock gears, correct. I am regearing so that goes out he window. The aftermarket gear sets sold are for 40/55/60/62/80r, no difference.
Click to expand...

Ah, right. Then you might want to go with the 80 series castings so the small parts will be available from the Toyota man for the longest time.
 
Another question:

Do the 91-92 3FE FJ80's with the semi float rear axle have the early or late style casting?
 
I've never heard of a cast housing breaking before a pinion did. I wouldn't worry yourself.
 
one thing that make me considere 80 series 3rd it's the FF related stuff .. I mean 40 / 60 series SF needs to keep space/access on the carrier so you can deal with axles C-Clips .. 80 series 3rd don't ..
 
Slowerthanu said:
I've never heard of a cast housing breaking before a pinion did. I wouldn't worry yourself.
Click to expand...

I get that, however, carrier deflection does break gears.

Let me rephrase the question:

Assume I have 2 FJ60 third members, and 2 FZJ80 third members. I want to build up a pair with new gears, bearings, lockers, etc. Which is the better platform to build on.
 
I can't comment on casting, bearings, or carrier strength but I will say if the older 9.5s are able to accept a thrust bolt that would have me leaning that way.

May want to do some research on how much strength they add. My understanding is that it's quite significant. I know it's a popular mod for the Land Rover guys. Also very common in factory over the road trucks.

Just my .02
 
Tapage said:
carriers can't be the same between SF and FF .. SF needs C-Clip access ..
Click to expand...

Not true. The main reason for access throught the carrier window is for installing the side gears. The access for the c-clips is through the same window. Even the aussie locker is the same for either carrier. You just do not have to install the c-clips and the disks that fit on either side of the cross shaft.
 
the older 3rd member casting is plenty strong enough to outlive what's inside of it......thin as hell ring gear and 27 spline pinion.
 
Not that I think it matters that much, but the 80 uses a smaller carrier bearing-it is the same as V-6 mini-truck.

FJ62 and earlier use the larger traditional Land Cruiser Carrier bearings.

The housing itself is plenty strong. It's really too bad Toyota did not go with the supported end of the pinion bearing like a Ford 9 inch or 14 bolt GM. That just looks like a better and stronger design.

Has anyone weighed them to see if there is a weight difference?


And BTW-FJ62 uses 9 x 37 ring and pinion. FJ80 up uses 10 x 41.
 
trd55 said:
Not true. The main reason for access throught the carrier window is for installing the side gears. The access for the c-clips is through the same window. Even the aussie locker is the same for either carrier. You just do not have to install the c-clips and the disks that fit on either side of the cross shaft.
Click to expand...

After further check on my FSM I must admit I was wrong.

Since all of our FF came with factory LSD all FF carriers I'm used to see / work on don't have any access.

apologizes for the wrong info ..
 
Tapage said:
After further check on my FSM I must admit I was wrong.

Since all of our FF came with factory LSD all FF carriers I'm used to see / work on don't have any access.

apologizes for the wrong info ..
Click to expand...

No worries..:cheers:
 
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